Mars Stratigraphy Mission

Science.gov (United States)

Budney, C. J.; Miller, S. L.; Cutts, J. A.

2000-01-01

The Mars Stratigraphy Mission lands a rover on the surface of Mars which descends down a cliff in Valles Marineris to study the stratigraphy. The rover carries a unique complement of instruments to analyze and age-date materials encountered during descent past 2 km of strata. The science objective for the Mars Stratigraphy Mission is to identify the geologic history of the layered deposits in the Valles Marineris region of Mars. This includes constraining the time interval for formation of these deposits by measuring the ages of various layers and determining the origin of the deposits (volcanic or sedimentary) by measuring their composition and imaging their morphology.

Risk-Constrained Dynamic Programming for Optimal Mars Entry, Descent, and Landing

Science.gov (United States)

Ono, Masahiro; Kuwata, Yoshiaki

2013-01-01

A chance-constrained dynamic programming algorithm was developed that is capable of making optimal sequential decisions within a user-specified risk bound. This work handles stochastic uncertainties over multiple stages in the CEMAT (Combined EDL-Mobility Analyses Tool) framework. It was demonstrated by a simulation of Mars entry, descent, and landing (EDL) using real landscape data obtained from the Mars Reconnaissance Orbiter. Although standard dynamic programming (DP) provides a general framework for optimal sequential decisionmaking under uncertainty, it typically achieves risk aversion by imposing an arbitrary penalty on failure states. Such a penalty-based approach cannot explicitly bound the probability of mission failure. A key idea behind the new approach is called risk allocation, which decomposes a joint chance constraint into a set of individual chance constraints and distributes risk over them. The joint chance constraint was reformulated into a constraint on an expectation over a sum of an indicator function, which can be incorporated into the cost function by dualizing the optimization problem. As a result, the chance-constraint optimization problem can be turned into an unconstrained optimization over a Lagrangian, which can be solved efficiently using a standard DP approach.

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

and Onboard Processing. The DEA incorpo-rates the circuit elements required for data processing, compression, and buffering. It also includes all power conversion and regulation capabilities for both the DEA and the camera head. The DEA has an 8 GB non-volatile flash memory plus 128 MB volatile storage. Images can be commanded as full-frame or sub-frame and the camera has autofocus and autoexposure capa-bilities. MAHLI can also acquire 720p, ~7 Hz high definition video. Onboard processing includes options for Bayer pattern filter interpolation, JPEG-based compression, and focus stack merging (z-stacking). Malin Space Science Systems (MSSS) built and will operate the MAHLI. Alliance Spacesystems, LLC, designed and built the lens mechanical assembly. MAHLI shares common electronics, detector, and software designs with the MSL Mars Descent Imager (MARDI) and the 2 MSL Mast Cameras (Mastcam). Pre-launch images of geologic materials imaged by MAHLI are online at: http://www.msss.com/msl/mahli/prelaunch_images/.

Assessment of environments for Mars Science Laboratory entry, descent, and surface operations

Science.gov (United States)

Vasavada, Ashwin R.; Chen, Allen; Barnes, Jeffrey R.; Burkhart, P. Daniel; Cantor, Bruce A.; Dwyer-Cianciolo, Alicia M.; Fergason, Robini L.; Hinson, David P.; Justh, Hilary L.; Kass, David M.; Lewis, Stephen R.; Mischna, Michael A.; Murphy, James R.; Rafkin, Scot C.R.; Tyler, Daniel; Withers, Paul G.

2012-01-01

The Mars Science Laboratory mission aims to land a car-sized rover on Mars' surface and operate it for at least one Mars year in order to assess whether its field area was ever capable of supporting microbial life. Here we describe the approach used to identify, characterize, and assess environmental risks to the landing and rover surface operations. Novel entry, descent, and landing approaches will be used to accurately deliver the 900-kg rover, including the ability to sense and "fly out" deviations from a best-estimate atmospheric state. A joint engineering and science team developed methods to estimate the range of potential atmospheric states at the time of arrival and to quantitatively assess the spacecraft's performance and risk given its particular sensitivities to atmospheric conditions. Numerical models are used to calculate the atmospheric parameters, with observations used to define model cases, tune model parameters, and validate results. This joint program has resulted in a spacecraft capable of accessing, with minimal risk, the four finalist sites chosen for their scientific merit. The capability to operate the landed rover over the latitude range of candidate landing sites, and for all seasons, was verified against an analysis of surface environmental conditions described here. These results, from orbital and model data sets, also drive engineering simulations of the rover's thermal state that are used to plan surface operations.

Guidance and Control Algorithms for the Mars Entry, Descent and Landing Systems Analysis

Science.gov (United States)

Davis, Jody L.; CwyerCianciolo, Alicia M.; Powell, Richard W.; Shidner, Jeremy D.; Garcia-Llama, Eduardo

2010-01-01

The purpose of the Mars Entry, Descent and Landing Systems Analysis (EDL-SA) study was to identify feasible technologies that will enable human exploration of Mars, specifically to deliver large payloads to the Martian surface. This paper focuses on the methods used to guide and control two of the contending technologies, a mid- lift-to-drag (L/D) rigid aeroshell and a hypersonic inflatable aerodynamic decelerator (HIAD), through the entry portion of the trajectory. The Program to Optimize Simulated Trajectories II (POST2) is used to simulate and analyze the trajectories of the contending technologies and guidance and control algorithms. Three guidance algorithms are discussed in this paper: EDL theoretical guidance, Numerical Predictor-Corrector (NPC) guidance and Analytical Predictor-Corrector (APC) guidance. EDL-SA also considered two forms of control: bank angle control, similar to that used by Apollo and the Space Shuttle, and a center-of-gravity (CG) offset control. This paper presents the performance comparison of these guidance algorithms and summarizes the results as they impact the technology recommendations for future study.

Mars Pathfinder and Mars Global Surveyor Outreach Compilation

Science.gov (United States)

1999-09-01

This videotape is a compilation of the best NASA JPL (Jet Propulsion Laboratory) videos of the Mars Pathfinder and Mars Global Surveyor missions. The mission is described using animation and narration as well as some actual footage of the entire sequence of mission events. Included within these animations are the spacecraft orbit insertion; descent to the Mars surface; deployment of the airbags and instruments; and exploration by Sojourner, the Mars rover. JPL activities at spacecraft control during significant mission events are also included at the end. The spacecraft cameras pan the surrounding Mars terrain and film Sojourner traversing the surface and inspecting rocks. A single, brief, processed image of the Cydonia region (Mars face) at an oblique angle from the Mars Global Surveyor is presented. A description of the Mars Pathfinder mission, instruments, landing and deployment process, Mars approach, spacecraft orbit insertion, rover operation are all described using computer animation. Actual color footage of Sojourner as well as a 360 deg pan of the Mars terrain surrounding the spacecraft is provided. Lower quality black and white photography depicting Sojourner traversing the Mars surface and inspecting Martian rocks also is included.

Entry, Descent and Landing Systems Analysis Study: Phase 1 Report

Science.gov (United States)

DwyerCianciolo, Alicia M.; Davis, Jody L.; Komar, David R.; Munk, Michelle M.; Samareh, Jamshid A.; Powell, Richard W.; Shidner, Jeremy D.; Stanley, Douglas O.; Wilhite, Alan W.; Kinney, David J.;

Direct-to-Earth Communications with Mars Science Laboratory During Entry, Descent, and Landing

Science.gov (United States)

Soriano, Melissa; Finley, Susan; Fort, David; Schratz, Brian; Ilott, Peter; Mukai, Ryan; Estabrook, Polly; Oudrhiri, Kamal; Kahan, Daniel; Satorius, Edgar

2013-01-01

Mars Science Laboratory (MSL) undergoes extreme heating and acceleration during Entry, Descent, and Landing (EDL) on Mars. Unknown dynamics lead to large Doppler shifts, making communication challenging. During EDL, a special form of Multiple Frequency Shift Keying (MFSK) communication is used for Direct-To-Earth (DTE) communication. The X-band signal is received by the Deep Space Network (DSN) at the Canberra Deep Space Communication complex, then down-converted, digitized, and recorded by open-loop Radio Science Receivers (RSR), and decoded in real-time by the EDL Data Analysis (EDA) System. The EDA uses lock states with configurable Fast Fourier Transforms to acquire and track the signal. RSR configuration and channel allocation is shown. Testing prior to EDL is discussed including software simulations, test bed runs with MSL flight hardware, and the in-flight end-to-end test. EDA configuration parameters and signal dynamics during pre-entry, entry, and parachute deployment are analyzed. RSR and EDA performance during MSL EDL is evaluated, including performance using a single 70-meter DSN antenna and an array of two 34-meter DSN antennas as a back up to the 70-meter antenna.

Preconditioned stochastic gradient descent optimisation for monomodal image registration

NARCIS (Netherlands)

Klein, S.; Staring, M.; Andersson, J.P.; Pluim, J.P.W.; Fichtinger, G.; Martel, A.; Peters, T.

2011-01-01

We present a stochastic optimisation method for intensity-based monomodal image registration. The method is based on a Robbins-Monro stochastic gradient descent method with adaptive step size estimation, and adds a preconditioning matrix. The derivation of the pre-conditioner is based on the

Propulsive Descent Technologies (PDT): Original Content Project

Data.gov (United States)

National Aeronautics and Space Administration — Future missions to Mars require landed mass that exceeds the capability of current entry, descent, and landing technology.  New technology and techniques are...

Mars Science Laboratory Entry Guidance Improvements for Mars 2018 (DRAFT)

Science.gov (United States)

Garcia-Llama, Eduardo; Winski, Richard G.; Shidner, Jeremy D.; Ivanov, Mark C.; Grover, Myron R.; Prakash, Ravi

2011-01-01

In 2011, the Mars Science Laboratory (MSL) will be launched in a mission to deliver the largest and most capable rover to date to the surface of Mars. A follow on MSL-derived mission, referred to as Mars 2018, is planned for 2018. Mars 2018 goals include performance enhancements of the Entry, Descent and Landing over that of its predecessor MSL mission of 2011. This paper will discuss the main elements of the modified 2018 EDL preliminary design that will increase performance on the entry phase of the mission. In particular, these elements will increase the parachute deploy altitude to allow for more time margin during the subsequent descent and landing phases and reduce the delivery ellipse size at parachute deploy through modifications in the entry reference trajectory design, guidance trigger logic design, and the effect of additional navigation hardware.

Terrain reconstruction based on descent images for the Chang’e III landing area

Directory of Open Access Journals (Sweden)

Xu Xinchao

2015-10-01

Full Text Available A new method that combined image matching and shape from shading for terrain reconstruction was proposed to solve the lack of terrain in the landing area of Chang'e III. First, the reflection equation was established based on the Lommel– Seeliger reflection model. After edge extraction, the gradients of points on the edge were solved. The normal vectors of adjacent points were obtained using the smoothness constraint. Furthermore, the gradients of residual points in the image were determined through evolution. The inadequacy of the reflection equation was eliminated by considering the gradient as the constraint of the reflection equation. The normal vector of each point could be obtained by solving the reflection equation. The terrain without coordinate information was reconstructed by iterating the vector field. After using scaleinvariant feature transform to extract matching points in the descent images, the terrain was converted to a lander centroid coordinate system. Experiments were carried out with MATLAB-simulated images, laboratory images, and descent images of Chang'e III. Results show that the proposed method performs better than the classical SFS algorithm. The new method can provide reference for other deep space exploration activities.

Mars Science Laboratory Heatshield Flight Data Analysis

Science.gov (United States)

Mahzari, Milad; White, Todd

2017-01-01

NASA Mars Science Laboratory (MSL), which landed the Curiosity rover on the surface of Mars on August 5th, 2012, was the largest and heaviest Mars entry vehicle representing a significant advancement in planetary entry, descent and landing capability. Hypersonic flight performance data was collected using MSLs on-board sensors called Mars Entry, Descent and Landing Instrumentation (MEDLI). This talk will give an overview of MSL entry and a description of MEDLI sensors. Observations from flight data will be examined followed by a discussion of analysis efforts to reconstruct surface heating from heatshields in-depth temperature measurements. Finally, a brief overview of MEDLI2 instrumentation, which will fly on NASAs Mars2020 mission, will be presented with a discussion on how lessons learned from MEDLI data affected the design of MEDLI2 instrumentation.

Mars Exploration Rover Terminal Descent Mission Modeling and Simulation

Science.gov (United States)

Raiszadeh, Behzad; Queen, Eric M.

2004-01-01

Because of NASA's added reliance on simulation for successful interplanetary missions, the MER mission has developed a detailed EDL trajectory modeling and simulation. This paper summarizes how the MER EDL sequence of events are modeled, verification of the methods used, and the inputs. This simulation is built upon a multibody parachute trajectory simulation tool that has been developed in POST I1 that accurately simulates the trajectory of multiple vehicles in flight with interacting forces. In this model the parachute and the suspended bodies are treated as 6 Degree-of-Freedom (6 DOF) bodies. The terminal descent phase of the mission consists of several Entry, Descent, Landing (EDL) events, such as parachute deployment, heatshield separation, deployment of the lander from the backshell, deployment of the airbags, RAD firings, TIRS firings, etc. For an accurate, reliable simulation these events need to be modeled seamlessly and robustly so that the simulations will remain numerically stable during Monte-Carlo simulations. This paper also summarizes how the events have been modeled, the numerical issues, and modeling challenges.

MISSION PROFILE AND DESIGN CHALLENGES FOR MARS LANDING EXPLORATION

OpenAIRE

J. Dong; Z. Sun; W. Rao; Y. Jia; L. Meng; C. Wang; B. Chen

2017-01-01

An orbiter and a descent module will be delivered to Mars in the Chinese first Mars exploration mission. The descent module is composed of a landing platform and a rover. The module will be released into the atmosphere by the orbiter and make a controlled landing on Martian surface. After landing, the rover will egress from the platform to start its science mission. The rover payloads mainly include the subsurface radar, terrain camera, multispectral camera, magnetometer, anemometer to achiev...

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.

Sparse Nonlinear Electromagnetic Imaging Accelerated With Projected Steepest Descent Algorithm

KAUST Repository

Desmal, Abdulla

2017-04-03

An efficient electromagnetic inversion scheme for imaging sparse 3-D domains is proposed. The scheme achieves its efficiency and accuracy by integrating two concepts. First, the nonlinear optimization problem is constrained using L₀ or L₁-norm of the solution as the penalty term to alleviate the ill-posedness of the inverse problem. The resulting Tikhonov minimization problem is solved using nonlinear Landweber iterations (NLW). Second, the efficiency of the NLW is significantly increased using a steepest descent algorithm. The algorithm uses a projection operator to enforce the sparsity constraint by thresholding the solution at every iteration. Thresholding level and iteration step are selected carefully to increase the efficiency without sacrificing the convergence of the algorithm. Numerical results demonstrate the efficiency and accuracy of the proposed imaging scheme in reconstructing sparse 3-D dielectric profiles.

Entry, Descent and Landing Systems Analysis: Exploration Class Simulation Overview and Results

Science.gov (United States)

DwyerCianciolo, Alicia M.; Davis, Jody L.; Shidner, Jeremy D.; Powell, Richard W.

2010-01-01

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to make in order to successfully land large payloads at Mars for both robotic and exploration or human-scale missions. The year one exploration class mission activity considered technologies capable of delivering a 40-mt payload. This paper provides an overview of the exploration class mission study, including technologies considered, models developed and initial simulation results from the EDL-SA year one effort.

Planetary entry, descent, and landing technologies

Science.gov (United States)

Pichkhadze, K.; Vorontsov, V.; Polyakov, A.; Ivankov, A.; Taalas, P.; Pellinen, R.; Harri, A.-M.; Linkin, V.

2003-04-01

Martian meteorological lander (MML) is intended for landing on the Martian surface in order to monitor the atmosphere at landing point for one Martian year. MMLs shall become the basic elements of a global network of meteorological mini-landers, observing the dynamics of changes of the atmospheric parameters on the Red Planet. The MML main scientific tasks are as follows: (1) Study of vertical structure of the Martian atmosphere throughout the MML descent; (2) On-surface meteorological observations for one Martian year. One of the essential factors influencing the lander's design is its entry, descent, and landing (EDL) sequence. During Phase A of the MML development, five different options for the lander's design were carefully analyzed. All of these options ensure the accomplishment of the above-mentioned scientific tasks with high effectiveness. CONCEPT A (conventional approach): Two lander options (with a parachute system + airbag and an inflatable airbrake + airbag) were analyzed. They are similar in terms of fulfilling braking phases and completely analogous in landing by means of airbags. CONCEPT B (innovative approach): Three lander options were analyzed. The distinguishing feature is the presence of inflatable braking units (IBU) in their configurations. SELECTED OPTION (innovative approach): Incorporating a unique design approach and modern technologies, the selected option of the lander represents a combination of the options analyzed in the framework of Concept B study. Currently, the selected lander option undergoes systems testing (Phase D1). Several MMLs can be delivered to Mars in frameworks of various missions as primary or piggybacking payload: (1) USA-led "Mars Scout" (2007); (2) France-led "NetLander" (2007/2009); (3) Russia-led "Mars-Deimos-Phobos sample return" (2007); (4) Independent mission (currently under preliminary study); etc.

MISSION PROFILE AND DESIGN CHALLENGES FOR MARS LANDING EXPLORATION

Directory of Open Access Journals (Sweden)

J. Dong

2017-07-01

Full Text Available An orbiter and a descent module will be delivered to Mars in the Chinese first Mars exploration mission. The descent module is composed of a landing platform and a rover. The module will be released into the atmosphere by the orbiter and make a controlled landing on Martian surface. After landing, the rover will egress from the platform to start its science mission. The rover payloads mainly include the subsurface radar, terrain camera, multispectral camera, magnetometer, anemometer to achieve the scientific investigation of the terrain, soil characteristics, material composition, magnetic field, atmosphere, etc. The landing process is divided into three phases (entry phase, parachute descent phase and powered descent phase, which are full of risks. There exit lots of indefinite parameters and design constrain to affect the selection of the landing sites and phase switch (mortaring the parachute, separating the heat shield and cutting off the parachute. A number of new technologies (disk-gap-band parachute, guidance and navigation, etc. need to be developed. Mars and Earth have gravity and atmosphere conditions that are significantly different from one another. Meaningful environmental conditions cannot be recreated terrestrially on earth. A full-scale flight validation on earth is difficult. Therefore the end-to-end simulation and some critical subsystem test must be considered instead. The challenges above and the corresponding design solutions are introduced in this paper, which can provide reference for the Mars exploration mission.

Mars-Moons Exploration, Reconnaissance and Landed Investigation (MERLIN)

Science.gov (United States)

Murchie, S. L.; Chabot, N. L.; Buczkowski, D.; Arvidson, R. E.; Castillo, J. C.; Peplowski, P. N.; Ernst, C. M.; Rivkin, A.; Eng, D.; Chmielewski, A. B.; Maki, J.; trebi-Ollenu, A.; Ehlmann, B. L.; Spence, H. E.; Horanyi, M.; Klingelhoefer, G.; Christian, J. A.

2015-12-01

The Mars-Moons Exploration, Reconnaissance and Landed Investigation (MERLIN) is a NASA Discovery mission proposal to explore the moons of Mars. Previous Mars-focused spacecraft have raised fundamental questions about Mars' moons: What are their origins and compositions? Why do the moons resemble primitive outer solar system D-type objects? How do geologic processes modify their surfaces? MERLIN answers these questions through a combination of orbital and landed measurements, beginning with reconnaissance of Deimos and investigation of the hypothesized Martian dust belts. Orbital reconnaissance of Phobos occurs, followed by low flyovers to characterize a landing site. MERLIN lands on Phobos, conducting a 90-day investigation. Radiation measurements are acquired throughout all mission phases. Phobos' size and mass provide a low-risk landing environment: controlled descent is so slow that the landing is rehearsed, but gravity is high enough that surface operations do not require anchoring. Existing imaging of Phobos reveals low regional slope regions suitable for landing, and provides knowledge for planning orbital and landed investigations. The payload leverages past NASA investments. Orbital imaging is accomplished by a dual multispectral/high-resolution imager rebuilt from MESSENGER/MDIS. Mars' dust environment is measured by the refurbished engineering model of LADEE/LDEX, and the radiation environment by the flight spare of LRO/CRaTER. The landed workspace is characterized by a color stereo imager updated from MER/HazCam. MERLIN's arm deploys landed instrumentation using proven designs from MER, Phoenix, and MSL. Elemental measurements are acquired by a modified version of Rosetta/APXS, and an uncooled gamma-ray spectrometer. Mineralogical measurements are acquired by a microscopic imaging spectrometer developed under MatISSE. MERLIN delivers seminal science traceable to NASA's Strategic Goals and Objectives, Science Plan, and the Decadal Survey. MERLIN's science

Quantification of Plume-Soil Interaction and Excavation Due to the Sky Crane Descent Stage

Science.gov (United States)

Vizcaino, Jeffrey; Mehta, Manish

2015-01-01

The quantification of the particulate erosion that occurs as a result of a rocket exhaust plume impinging on soil during extraterrestrial landings is critical for future robotic and human lander mission design. The aerodynamic environment that results from the reflected plumes results in dust lifting, site alteration and saltation, all of which create a potentially erosive and contaminant heavy environment for the lander vehicle and any surrounding structures. The Mars Science Lab (MSL), weighing nearly one metric ton, required higher levels of thrust from its retro propulsive systems and an entirely new descent system to minimize these effects. In this work we seek to quantify plume soil interaction and its resultant soil erosion caused by the MSL's Sky Crane descent stage engines by performing three dimensional digital terrain and elevation mapping of the Curiosity rover's landing site. Analysis of plume soil interaction altitude and time was performed by detailed examination of the Mars Descent Imager (MARDI) still frames and reconstructed inertial measurement unit (IMU) sensor data. Results show initial plume soil interaction from the Sky Crane's eight engines began at ground elevations greater than 60 meters and more than 25 seconds before the rovers' touchdown event. During this time, viscous shear erosion (VSE) was dominant typically resulting in dusting of the surface with flow propagating nearly parallel to the surface. As the vehicle descended and decreased to four powered engines plume-plume and plume soil interaction increased the overall erosion rate at the surface. Visibility was greatly reduced at a height of roughly 20 meters above the surface and fell to zero ground visibility shortly after. The deployment phase of the Sky Crane descent stage hovering at nearly six meters above the surface showed the greatest amount of erosion with several large particles of soil being kicked up, recirculated, and impacting the bottom of the rover chassis. Image

Mars Molniya Orbit Atmospheric Resource Mining

Data.gov (United States)

National Aeronautics and Space Administration — Mars planetary surface access is one of NASA's biggest technical challenges involving advanced entry, descent, and landing (EDL) technologies and methods. This NASA...

Curiosity's Mars Hand Lens Imager (MAHLI) Investigation

Science.gov (United States)

Edgett, Kenneth S.; Yingst, R. Aileen; Ravine, Michael A.; Caplinger, Michael A.; Maki, Justin N.; Ghaemi, F. Tony; Schaffner, Jacob A.; Bell, James F.; Edwards, Laurence J.; Herkenhoff, Kenneth E.; Heydari, Ezat; Kah, Linda C.; Lemmon, Mark T.; Minitti, Michelle E.; Olson, Timothy S.; Parker, Timothy J.; Rowland, Scott K.; Schieber, Juergen; Sullivan, Robert J.; Sumner, Dawn Y.; Thomas, Peter C.; Jensen, Elsa H.; Simmonds, John J.; Sengstacken, Aaron J.; Wilson, Reg G.; Goetz, Walter

2012-01-01

The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ?5 km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ?2.1 cm to infinity. At the minimum working distance, image pixel scale is ?14 μm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI?s resolution is comparable at ?30 μm per pixel. Onboard capabilities include autofocus, auto-exposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage.

First CaSSIS Colour Images of Mars

Science.gov (United States)

Alfred, M.; Pommerol, A.; Thomas, N.; Cremonese, G.

2017-12-01

The Colour and Stereo Surface Imaging System (CaSSIS) on board ESA's Exomars Trace Gas Orbiter has acquired its first images of the surface of Mars on the 22nd and 26th of November, 2016. This commissioning campaign on the initial capture orbit was highly successful, allowing us to test the instrument, establish its performance and collect detailed images from the surface. Many of them have been publicly released within days following acquisition. These images and other commissioning data have demonstrated that the capabilities of the instrument are fully in-line with expectation. Although a colour image of Phobos produced from observations acquired on the 26th of November was rapidly released, the calibration and production of colour images from the surface of Mars proved to be more challenging. Having fixed technical issues, acquired and processed necessary in-flight calibration data, we have recently recalibrated the whole dataset, improving significantly the quality of the data and allowing us, for the first time, to produce high-quality colour images from the surface of Mars with CaSSIS data. The absolute calibration of the instrument is currently verified using stellar observations but the values of reflectivity obtained in each of the four colour channels for the surfaces of Mars and Phobos already show good consistency with other orbital data. The timing of CaSSIS acquisitions is very accurate and results in good colour matching, as already verified on-ground during the calibration campaign. The first few images acquired on the 22nd of November, shortly after TGO crossed the morning terminator, show unique views of the dusty terrains of the Tharsis region with solar incidence angle ranging between 60° and 80°. Comparison with images of the same areas acquired at later local times by other orbiters shows intriguing differences, related in particular to the brightness and colour of the floor of dust-filled craters that look bluer in the morning than in the

Russian contribution to the ExoMars project

Science.gov (United States)

Zelenyi, L.; Korablev, O.; Rodionov, D.; Khartov, V.; Martynov, M.; Lukyanchikov, A.

2014-04-01

The ExoMars ESA-led mission is dedicated to study of Mars and in particular its habitability. It consists of two launches, one planned in 2016 to deliver to Mars a telecommunication and science orbiter Trace Gas Orbiter (TGO) and a demonstrator of entry into the atmosphere and landing on the Mars surface, Entry, Descent and Landing Demonstrator Module (EDM). In 2018 a rover with drilling capability will be delivered to the surface of Mars. Since 2012 this mission, previously planned in cooperation with NASA is being developed in cooperation with Roscosmos. Both launches are planned with Proton-Breeze. In 2016 Russia contributes a significant part of the TGO science payload. In 2018 the landing will be provided by a joint effort capitalizing on the EDM technology. Russia contributes few science instruments for the rover, and leads the development of a long-living geophysical platform on the surface of Mars. Russian science instruments for TGO, the Atmospheric Chemistry Suite (ACS) and the Fine Resolution Epithermal Neutrons Detector (FREND) constituent a half of its scientific payload, European instrument being NOMAD for mapping and detection of trace species, and CASSIS camera for high-resolution mapping of target areas. The ACS package consists of three spectrometers covering spectral range from 0.7 to 17 μm with spectral resolving power reaching 50000. It is dedicated to studies of the composition of the Martian atmosphere and the Martian climate. FREND is a neutron detector with a collimation module, which significantly narrows the field of view of the instrument, allowing to create higher resolution maps of hydrogen-abundant regions on Mars. The spatial resolution of FREND will be ~40 km from the 400- km TGO orbit that is ~10 times better than HEND on Mars-Odyssey. Additionally, FREND includes a dosimeter module for monitoring radiation levels in orbit around Mars. In the 2018 mission, Russia takes the major responsibility of the descent module. The primary

Mars Global Reference Atmospheric Model 2010 Version: Users Guide

Science.gov (United States)

Justh, H. L.

2014-01-01

This Technical Memorandum (TM) presents the Mars Global Reference Atmospheric Model 2010 (Mars-GRAM 2010) and its new features. Mars-GRAM is an engineering-level atmospheric model widely used for diverse mission applications. Applications include systems design, performance analysis, and operations planning for aerobraking, entry, descent and landing, and aerocapture. Additionally, this TM includes instructions on obtaining the Mars-GRAM source code and data files as well as running Mars-GRAM. It also contains sample Mars-GRAM input and output files and an example of how to incorporate Mars-GRAM as an atmospheric subroutine in a trajectory code.

MARS spectral molecular imaging of lamb tissue: data collection and image analysis

CERN Document Server

Aamir, R; Bateman, C.J.; Butler, A.P.H.; Butler, P.H.; Anderson, N.G.; Bell, S.T.; Panta, R.K.; Healy, J.L.; Mohr, J.L.; Rajendran, K.; Walsh, M.F.; Ruiter, N.de; Gieseg, S.P.; Woodfield, T.; Renaud, P.F.; Brooke, L.; Abdul-Majid, S.; Clyne, M.; Glendenning, R.; Bones, P.J.; Billinghurst, M.; Bartneck, C.; Mandalika, H.; Grasset, R.; Schleich, N.; Scott, N.; Nik, S.J.; Opie, A.; Janmale, T.; Tang, D.N.; Kim, D.; Doesburg, R.M.; Zainon, R.; Ronaldson, J.P.; Cook, N.J.; Smithies, D.J.; Hodge, K.

2014-01-01

Spectral molecular imaging is a new imaging technique able to discriminate and quantify different components of tissue simultaneously at high spatial and high energy resolution. Our MARS scanner is an x-ray based small animal CT system designed to be used in the diagnostic energy range (20 to 140 keV). In this paper, we demonstrate the use of the MARS scanner, equipped with the Medipix3RX spectroscopic photon-processing detector, to discriminate fat, calcium, and water in tissue. We present data collected from a sample of lamb meat including bone as an illustrative example of human tissue imaging. The data is analyzed using our 3D Algebraic Reconstruction Algorithm (MARS-ART) and by material decomposition based on a constrained linear least squares algorithm. The results presented here clearly show the quantification of lipid-like, water-like and bone-like components of tissue. However, it is also clear to us that better algorithms could extract more information of clinical interest from our data. Because we ...

Identification of the Beagle 2 lander on Mars

Science.gov (United States)

Bridges, J. C.; Clemmet, J.; Croon, M.; Sims, M. R.; Pullan, D.; Muller, J.-P.; Tao, Y.; Xiong, S.; Putri, A. R.; Parker, T.; Turner, S. M. R.; Pillinger, J. M.

2017-10-01

The 2003 Beagle 2 Mars lander has been identified in Isidis Planitia at 90.43° E, 11.53° N, close to the predicted target of 90.50° E, 11.53° N. Beagle 2 was an exobiology lander designed to look for isotopic and compositional signs of life on Mars, as part of the European Space Agency Mars Express (MEX) mission. The 2004 recalculation of the original landing ellipse from a 3-sigma major axis from 174 km to 57 km, and the acquisition of Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE) imagery at 30 cm per pixel across the target region, led to the initial identification of the lander in 2014. Following this, more HiRISE images, giving a total of 15, including red and blue-green colours, were obtained over the area of interest and searched, which allowed sub-pixel imaging using super high-resolution techniques. The size (approx. 1.5 m), distinctive multilobed shape, high reflectivity relative to the local terrain, specular reflections, and location close to the centre of the planned landing ellipse led to the identification of the Beagle 2 lander. The shape of the imaged lander, although to some extent masked by the specular reflections in the various images, is consistent with deployment of the lander lid and then some or all solar panels. Failure to fully deploy the panels-which may have been caused by damage during landing-would have prohibited communication between the lander and MEX and commencement of science operations. This implies that the main part of the entry, descent and landing sequence, the ejection from MEX, atmospheric entry and parachute deployment, and landing worked as planned with perhaps only the final full panel deployment failing.

Identification of the Beagle 2 lander on Mars.

Science.gov (United States)

Bridges, J C; Clemmet, J; Croon, M; Sims, M R; Pullan, D; Muller, J-P; Tao, Y; Xiong, S; Putri, A R; Parker, T; Turner, S M R; Pillinger, J M

2017-10-01

The 2003 Beagle 2 Mars lander has been identified in Isidis Planitia at 90.43° E, 11.53° N, close to the predicted target of 90.50° E, 11.53° N. Beagle 2 was an exobiology lander designed to look for isotopic and compositional signs of life on Mars, as part of the European Space Agency Mars Express (MEX) mission. The 2004 recalculation of the original landing ellipse from a 3-sigma major axis from 174 km to 57 km, and the acquisition of Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment (HiRISE) imagery at 30 cm per pixel across the target region, led to the initial identification of the lander in 2014. Following this, more HiRISE images, giving a total of 15, including red and blue-green colours, were obtained over the area of interest and searched, which allowed sub-pixel imaging using super high-resolution techniques. The size (approx. 1.5 m), distinctive multilobed shape, high reflectivity relative to the local terrain, specular reflections, and location close to the centre of the planned landing ellipse led to the identification of the Beagle 2 lander. The shape of the imaged lander, although to some extent masked by the specular reflections in the various images, is consistent with deployment of the lander lid and then some or all solar panels. Failure to fully deploy the panels-which may have been caused by damage during landing-would have prohibited communication between the lander and MEX and commencement of science operations. This implies that the main part of the entry, descent and landing sequence, the ejection from MEX, atmospheric entry and parachute deployment, and landing worked as planned with perhaps only the final full panel deployment failing.

Powered Flight Design and Reconstructed Performance Summary for the Mars Science Laboratory Mission

Science.gov (United States)

Sell, Steven; Chen, Allen; Davis, Jody; San Martin, Miguel; Serricchio, Frederick; Singh, Gurkirpal

2013-01-01

The Powered Flight segment of Mars Science Laboratory's (MSL) Entry, Descent, and Landing (EDL) system extends from backshell separation through landing. This segment is responsible for removing the final 0.1% of the kinetic energy dissipated during EDL and culminating with the successful touchdown of the rover on the surface of Mars. Many challenges exist in the Powered Flight segment: extraction of Powered Descent Vehicle from the backshell, performing a 300m divert maneuver to avoid the backshell and parachute, slowing the descent from 85 m/s to 0.75 m/s and successfully lowering the rover on a 7.5m bridle beneath the rocket-powered Descent Stage and gently placing it on the surface using the Sky Crane Maneuver. Finally, the nearly-spent Descent Stage must execute a Flyaway maneuver to ensure surface impact a safe distance from the Rover. This paper provides an overview of the powered flight design, key features, and event timeline. It also summarizes Curiosity's as flown performance on the night of August 5th as reconstructed by the flight team.

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.

FUSION OF MULTI-SCALE DEMS FROM DESCENT AND NAVCM IMAGES OF CHANG’E-3 USING COMPRESSED SENSING METHOD

Directory of Open Access Journals (Sweden)

M. Peng

2017-07-01

Full Text Available The multi-source DEMs generated using the images acquired in the descent and landing phase and after landing contain supplementary information, and this makes it possible and beneficial to produce a higher-quality DEM through fusing the multi-scale DEMs. The proposed fusion method consists of three steps. First, source DEMs are split into small DEM patches, then the DEM patches are classified into a few groups by local density peaks clustering. Next, the grouped DEM patches are used for sub-dictionary learning by stochastic coordinate coding. The trained sub-dictionaries are combined into a dictionary for sparse representation. Finally, the simultaneous orthogonal matching pursuit (SOMP algorithm is used to achieve sparse representation. We use the real DEMs generated from Chang’e-3 descent images and navigation camera (Navcam stereo images to validate the proposed method. Through the experiments, we have reconstructed a seamless DEM with the highest resolution and the largest spatial coverage among the input data. The experimental results demonstrated the feasibility of the proposed method.

Meteorological Predictions in Support of the Mars Science Laboratory Entry, Descent and Landing

Science.gov (United States)

Rothchild, A.; Rafkin, S. C.; Pielke, R. A., Sr.

2010-12-01

The Mars Science Laboratory (MSL) entry, descent, and landing (EDL) system employs a standard parachute strategy followed by a new sky crane concept where the rover is lowered to the ground via a tether from a hovering entry vehicle. As with previous missions, EDL system performance is sensitive to atmospheric conditions. While some observations characterizing the mean, large-scale atmospheric temperature and density data are available, there is effectively no information on the atmospheric conditions and variability at the scale that directly affects the spacecraft. In order to evaluate EDL system performance and to assess landing hazards and risk, it is necessary to simulate the atmosphere with a model that provides data at the appropriate spatial and temporal scales. Models also permit the study of the impact of the highly variable atmospheric dust loading on temperature, density and winds. There are four potential MSL landing sites: Mawrth Valle (22.3 N, 16.5W) , Gale Crater (5.4S, 137.7E), Holden Crater (26.1S, 34W), and Eberswalde Crater (24S, 33W). The final selection of the landing site will balance potential science return against landing and operational risk. Atmospheric modeling studies conducted with the Mars Regional Atmospheric Modeling System (MRAMS) is an integral part of the selection process. At each of the landing sites, a variety of simulations are conducted. The first type of simulations provide baseline predictions under nominal atmospheric dust loading conditions within the landing site window of ~Ls 150-170. The second type of simulation explores situations with moderate and high global atmospheric dust loading. The final type of simulation investigates the impact of local dust disturbances at the landing site. Mean and perturbation fields from each type of simulation at each of the potential landing sites are presented in comparison with the engineering performance limitations for the MSL EDL system. Within the lowest scale height, winds

In Situ Strategy of the 2011 Mars Science Laboratory to Investigate the Habitability of Ancient Mars

Science.gov (United States)

Mahaffy, Paul R.

2011-01-01

The ten science investigations of the 2011 Mars Science Laboratory (MSL) Rover named "Curiosity" seek to provide a quantitative assessment of habitability through chemical and geological measurements from a highly capable robotic' platform. This mission seeks to understand if the conditions for life on ancient Mars are preserved in the near-surface geochemical record. These substantial payload resources enabled by MSL's new entry descent and landing (EDL) system have allowed the inclusion of instrument types nevv to the Mars surface including those that can accept delivered sample from rocks and soils and perform a wide range of chemical, isotopic, and mineralogical analyses. The Chemistry and Mineralogy (CheMin) experiment that is located in the interior of the rover is a powder x-ray Diffraction (XRD) and X-ray Fluorescence (XRF) instrument that provides elemental and mineralogical information. The Sample Analysis at Mars (SAM) suite of instruments complements this experiment by analyzing the volatile component of identically processed samples and by analyzing atmospheric composition. Other MSL payload tools such as the Mast Camera (Mastcam) and the Chemistry & Camera (ChemCam) instruments are utilized to identify targets for interrogation first by the arm tools and subsequent ingestion into SAM and CheMin using the Sample Acquisition, Processing, and Handling (SA/SPaH) subsystem. The arm tools include the Mars Hand Lens Imager (MAHLI) and the Chemistry and Alpha Particle X-ray Spectrometer (APXX). The Dynamic Albedo of Neutrons (DAN) instrument provides subsurface identification of hydrogen such as that contained in hydrated minerals

IDENTIFYING SURFACE CHANGES ON HRSC IMAGES OF THE MARS SOUTH POLAR RESIDUAL CAP (SPRC

Directory of Open Access Journals (Sweden)

A. R. D. Putri

2016-06-01

Full Text Available The surface of Mars has been an object of interest for planetary research since the launch of Mariner 4 in 1964. Since then different cameras such as the Viking Visual Imaging Subsystem (VIS, Mars Global Surveyor (MGS Mars Orbiter Camera (MOC, and Mars Reconnaissance Orbiter (MRO Context Camera (CTX and High Resolution Imaging Science Experiment (HiRISE have been imaging its surface at ever higher resolution. The High Resolution Stereo Camera (HRSC on board of the European Space Agency (ESA Mars Express, has been imaging the Martian surface, since 25th December 2003 until the present-day. HRSC has covered 100 % of the surface of Mars, about 70 % of the surface with panchromatic images at 10-20 m/pixel, and about 98 % at better than 100 m/pixel (Neukum et. al., 2004, including the polar regions of Mars. The Mars polar regions have been studied intensively recently by analysing images taken by the Mars Express and MRO missions (Plaut et al., 2007. The South Polar Residual Cap (SPRC does not change very much in volume overall but there are numerous examples of dynamic phenomena associated with seasonal changes in the atmosphere. In particular, we can examine the time variation of layers of solid carbon dioxide and water ice with dust deposition (Bibring, 2004, spider-like channels (Piqueux et al., 2003 and so-called Swiss Cheese Terrain (Titus et al., 2004. Because of seasonal changes each Martian year, due to the sublimation and deposition of water and CO2 ice on the Martian south polar region, clearly identifiable surface changes occur in otherwise permanently icy region. In this research, good quality HRSC images of the Mars South Polar region are processed based on previous identification as the optimal coverage of clear surfaces (Campbell et al., 2015. HRSC images of the Martian South Pole are categorized in terms of quality, time, and location to find overlapping areas, processed into high quality Digital Terrain Models (DTMs and

An Optimized Method for Terrain Reconstruction Based on Descent Images

Directory of Open Access Journals (Sweden)

Xu Xinchao

2016-02-01

Full Text Available An optimization method is proposed to perform high-accuracy terrain reconstruction of the landing area of Chang’e III. First, feature matching is conducted using geometric model constraints. Then, the initial terrain is obtained and the initial normal vector of each point is solved on the basis of the initial terrain. By changing the vector around the initial normal vector in small steps a set of new vectors is obtained. By combining these vectors with the direction of light and camera, the functions are set up on the basis of a surface reflection model. Then, a series of gray values is derived by solving the equations. The new optimized vector is recorded when the obtained gray value is closest to the corresponding pixel. Finally, the optimized terrain is obtained after iteration of the vector field. Experiments were conducted using the laboratory images and descent images of Chang’e III. The results showed that the performance of the proposed method was better than that of the classical feature matching method. It can provide a reference for terrain reconstruction of the landing area in subsequent moon exploration missions.

Automatic Detection of Changes on Mars Surface from High-Resolution Orbital Images

Science.gov (United States)

Sidiropoulos, Panagiotis; Muller, Jan-Peter

2017-04-01

Over the last 40 years Mars has been extensively mapped by several NASA and ESA orbital missions, generating a large image dataset comprised of approximately 500,000 high-resolution images (of citizen science can be employed for training and verification it is unsuitable for planetwide systematic change detection. In this work, we introduce a novel approach in planetary image change detection, which involves a batch-mode automatic change detection pipeline that identifies regions that have changed. This is tested in anger, on tens of thousands of high-resolution images over the MC11 quadrangle [5], acquired by CTX, HRSC, THEMIS-VIS and MOC-NA instruments [1]. We will present results which indicate a substantial level of activity in this region of Mars, including instances of dynamic natural phenomena that haven't been cataloged in the planetary science literature before. We will demonstrate the potential and usefulness of such an automatic approach in planetary science change detection. Acknowledgments: The research leading to these results has received funding from the STFC "MSSL Consolidated Grant" ST/K000977/1 and partial support from the European Union's Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement n° 607379. References: [1] P. Sidiropoulos and J. - P. Muller (2015) On the status of orbital high-resolution repeat imaging of Mars for the observation of dynamic surface processes. Planetary and Space Science, 117: 207-222. [2] O. Aharonson, et al. (2003) Slope streak formation and dust deposition rates on Mars. Journal of Geophysical Research: Planets, 108(E12):5138 [3] A. McEwen, et al. (2011) Seasonal flows on warm martian slopes. Science, 333 (6043): 740-743. [4] S. Byrne, et al. (2009) Distribution of mid-latitude ground ice on mars from new impact craters. Science, 325(5948):1674-1676. [5] K. Gwinner, et al (2016) The High Resolution Stereo Camera (HRSC) of Mars Express and its approach to science analysis and mapping for Mars and

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.

Astrobiology and the Human Exploration of Mars

Science.gov (United States)

Levine, Joel S.; Garvin, James B.; Drake, B. G.; Beaty, David

2010-01-01

In March 2007, the Mars Exploration Program Analysis Group (MEPAG) chartered the Human Exploration of Mars Science Analysis Group (HEM-SAG), co-chaired by J. B. Garvin and J. S. Levine and consisting of about 30 Mars scientists from the U.S. and Europe. HEM-SAG was one of a half dozen teams charted by NASA to consider the human exploration of Mars. Other teams included: Mars Entry, Descent and Landing, Human Health and Performance, Flight and Surface Systems, and Heliospheric/Astrophysics. The results of these Mars teams and the development of an architecture for the human exploration of Mars were summarized in two recent publications: Human Exploration of Mars Design Reference Architecture 5.0, NASA Special Publication-2009-566 (B. G. Drake, Editor), 100 pages, July 2009 and Human Exploration of Mars Design Reference Architecture 5.0, NASA Special Publication-2009-566 Addendum (B. G. Drake, Editor), 406 pages, July 2009. This presentation summarizes the HEM-SAG conclusions on astrobiology and the search for life on Mars by humans.

Three-dimensional sparse electromagnetic imaging accelerated by projected steepest descent

KAUST Repository

Desmal, Abdulla

2016-11-02

An efficient and accurate scheme for solving the nonlinear electromagnetic inverse scattering problem on three-dimensional sparse investigation domains is proposed. The minimization problem is constructed in such a way that the data misfit between measurements and scattered fields (which are expressed as a nonlinear function of the contrast) is constrained by the contrast\\'s first norm. The resulting minimization problem is solved using nonlinear Landweber iterations accelerated using a steepest descent algorithm. A projection operator is applied at every iteration to enforce the sparsity constraint by thresholding the result of that iteration. Steepest descent algorithm ensures accelerated and convergent solution by utilizing larger iteration steps selected based on a necessary B-condition.

MARS Spectral Imaging: From High-Energy Physics to a Biomedical Business

CERN Multimedia

CERN. Geneva

2017-01-01

Abstract MARS spectral scanners provide colour X-Ray images. Current MARS pre-clinical scanners enable researchers and clinicians to measure biochemical and physiological processes in specimens, and animal models of disease. The scanners have developed from a 10 year scientific collaboration between New Zealand and CERN. In parallel a company, MARS Bioimaging Ltd, was founded to commercialise the technology by productising the scanner and selling it to biomedical users around the world. The New Zealand team is now more than 30 people including staff and students from the fields of physics, engineering, computing, maths, radiology, cardiology, biochemistry, oncology, and orthopaedics. Current work with pre-clinical scanners has concluded that the technology will be  useful in heart disease, stroke, arthritis, joint replacements, and cancer. In late 2014, the government announced funding for NZ to build a MARS scanner capable of imaging humans. Bio Professor Anthony Butler is a radiologist wit...

Feeding People's Curiosity: Leveraging the Cloud for Automatic Dissemination of Mars Images

Science.gov (United States)

Knight, David; Powell, Mark

2013-01-01

Smartphones and tablets have made wireless computing ubiquitous, and users expect instant, on-demand access to information. The Mars Science Laboratory (MSL) operations software suite, MSL InterfaCE (MSLICE), employs a different back-end image processing architecture compared to that of the Mars Exploration Rovers (MER) in order to better satisfy modern consumer-driven usage patterns and to offer greater server-side flexibility. Cloud services are a centerpiece of the server-side architecture that allows new image data to be delivered automatically to both scientists using MSLICE and the general public through the MSL website (http://mars.jpl.nasa.gov/msl/).

Transportation-Driven Mars Surface Operations Supporting an Evolvable Mars Campaign

Science.gov (United States)

Toups, Larry; Brown, Kendall; Hoffman, Stephen J.

2015-01-01

This paper describes the results of a study evaluating options for supporting a series of human missions to a single Mars surface destination. In this scenario the infrastructure emplaced during previous visits to this site is leveraged in following missions. The goal of this single site approach to Mars surface infrastructure is to enable "Steady State" operations by at least 4 crew for up to 500 sols at this site. These characteristics, along with the transportation system used to deliver crew and equipment to and from Mars, are collectively known as the Evolvable Mars Campaign (EMC). Information in this paper is presented in the sequence in which it was accomplished. First, a logical buildup sequence of surface infrastructure was developed to achieve the desired "Steady State" operations on the Mars surface. This was based on a concept of operations that met objectives of the EMC. Second, infrastructure capabilities were identified to carry out this concept of operations. Third, systems (in the form of conceptual elements) were identified to provide these capabilities. This included top-level mass, power and volume estimates for these elements. Fourth, the results were then used in analyses to evaluate three options (18t, 27t, and 40t landed mass) of Mars Lander delivery capability to the surface. Finally, Mars arrival mass estimates were generated based upon the entry, descent, and landing requirements for inclusion in separate assessments of in-space transportation capabilities for the EMC.

Compact Micro-Imaging Spectrometer (CMIS): Investigation of Imaging Spectroscopy and Its Application to Mars Geology and Astrobiology

Science.gov (United States)

Staten, Paul W.

2005-01-01

Future missions to Mars will attempt to answer questions about Mars' geological and biological history. The goal of the CMIS project is to design, construct, and test a capable, multi-spectral micro-imaging spectrometer use in such missions. A breadboard instrument has been constructed with a micro-imaging camera and Several multi-wavelength LED illumination rings. Test samples have been chosen for their interest to spectroscopists, geologists and astrobiologists. Preliminary analysis has demonstrated the advantages of isotropic illumination and micro-imaging spectroscopy over spot spectroscopy.

Sparse Nonlinear Electromagnetic Imaging Accelerated With Projected Steepest Descent Algorithm

KAUST Repository

Desmal, Abdulla; Bagci, Hakan

2017-01-01

steepest descent algorithm. The algorithm uses a projection operator to enforce the sparsity constraint by thresholding the solution at every iteration. Thresholding level and iteration step are selected carefully to increase the efficiency without

Science applications of a multispectral microscopic imager for the astrobiological exploration of Mars.

Science.gov (United States)

Núñez, Jorge I; Farmer, Jack D; Sellar, R Glenn; Swayze, Gregg A; Blaney, Diana L

2014-02-01

Future astrobiological missions to Mars are likely to emphasize the use of rovers with in situ petrologic capabilities for selecting the best samples at a site for in situ analysis with onboard lab instruments or for caching for potential return to Earth. Such observations are central to an understanding of the potential for past habitable conditions at a site and for identifying samples most likely to harbor fossil biosignatures. The Multispectral Microscopic Imager (MMI) provides multispectral reflectance images of geological samples at the microscale, where each image pixel is composed of a visible/shortwave infrared spectrum ranging from 0.46 to 1.73 μm. This spectral range enables the discrimination of a wide variety of rock-forming minerals, especially Fe-bearing phases, and the detection of hydrated minerals. The MMI advances beyond the capabilities of current microimagers on Mars by extending the spectral range into the infrared and increasing the number of spectral bands. The design employs multispectral light-emitting diodes and an uncooled indium gallium arsenide focal plane array to achieve a very low mass and high reliability. To better understand and demonstrate the capabilities of the MMI for future surface missions to Mars, we analyzed samples from Mars-relevant analog environments with the MMI. Results indicate that the MMI images faithfully resolve the fine-scale microtextural features of samples and provide important information to help constrain mineral composition. The use of spectral endmember mapping reveals the distribution of Fe-bearing minerals (including silicates and oxides) with high fidelity, along with the presence of hydrated minerals. MMI-based petrogenetic interpretations compare favorably with laboratory-based analyses, revealing the value of the MMI for future in situ rover-mediated astrobiological exploration of Mars. Mars-Microscopic imager-Multispectral imaging-Spectroscopy-Habitability-Arm instrument.

Descent imager/spectral radiometer (DISR) instrument aboard the Huygens probe of Titan

Science.gov (United States)

Tomasko, Martin G.; Doose, Lyn R.; Smith, Peter H.; Fellows, C.; Rizk, B.; See, C.; Bushroe, M.; McFarlane, E.; Wegryn, E.; Frans, E.; Clark, R.; Prout, M.; Clapp, S.

1996-10-01

The Huygen's probe of the atmosphere of Saturn's moon Titan includes one optical instrument sensitive to the wavelengths of solar radiation. The goals of this investigation fall into four broad areas: 1) the measurement of the profile of solar heating to support an improved understanding of the thermal balance of Titan and the role of the greenhouse effect in maintaining Titan's temperature structure; 2) the measurement of the size, vertical distribution, and optical properties of the aerosol and cloud particles in Titan's atmosphere to support studies of the origin, chemistry, life cycles, and role in the radiation balance of Titan played by these particles; 3) the composition of the atmosphere, particularly the vertical profile of the mixing ratio of methane, a condensable constituent in Titan's atmosphere; and 4) the physical state, composition, topography, and physical processes at work in determining the nature of the surface of Titan and its interaction with Titan's atmosphere. In order to accomplish these objectives, the Descent Imager/Spectral Radiometer (DISR) instrument makes extensive use of fiber optics to bring the light from several different sets of foreoptics to a silicon CCD detector, to a pair of InGaAs linear array detectors, and to three silicon photometers. Together these detectors permit DISR to make panoramic images of the clouds and surface of Titan, to measure the spectrum of upward and downward streaming sunlight from 350 to 1700 nm at a resolving power of about 200, to measure the reflection spectrum of >= 3000 locations on the surface, to measure the brightness and polarization of the solar aureole between 4 and 30 degrees from the sun at 500 and 935 nm, to separate the direct and diffuse downward solar flux at each wavelength measured, and to measure the continuous reflection spectrum of the ground between 850 and 1600 nm using an onboard lamp in the last 100 m of the descent.

SU-E-I-13: Evaluation of Metal Artifact Reduction (MAR) Software On Computed Tomography (CT) Images

International Nuclear Information System (INIS)

Huang, V; Kohli, K

2015-01-01

Purpose: A new commercially available metal artifact reduction (MAR) software in computed tomography (CT) imaging was evaluated with phantoms in the presence of metals. The goal was to assess the ability of the software to restore the CT number in the vicinity of the metals without impacting the image quality. Methods: A Catphan 504 was scanned with a GE Optima RT 580 CT scanner (GE Healthcare, Milwaukee, WI) and the images were reconstructed with and without the MAR software. Both datasets were analyzed with Image Owl QA software (Image Owl Inc, Greenwich, NY). CT number sensitometry, MTF, low contrast, uniformity, noise and spatial accuracy were compared for scans with and without MAR software. In addition, an in-house made phantom was scanned with and without a stainless steel insert at three different locations. The accuracy of the CT number and metal insert dimension were investigated as well. Results: Comparisons between scans with and without MAR algorithm on the Catphan phantom demonstrate similar results for image quality. However, noise was slightly higher for the MAR algorithm. Evaluation of the CT number at various locations of the in-house made phantom was also performed. The baseline HU, obtained from the scan without metal insert, was compared to scans with the stainless steel insert at 3 different locations. The HU difference between the baseline scan versus metal scan was improved when the MAR algorithm was applied. In addition, the physical diameter of the stainless steel rod was over-estimated by the MAR algorithm by 0.9 mm. Conclusion: This work indicates with the presence of metal in CT scans, the MAR algorithm is capable of providing a more accurate CT number without compromising the overall image quality. Future work will include the dosimetric impact on the MAR algorithm

MMPM - Mars MetNet Precursor Mission

Science.gov (United States)

Harri, A.-M.; Schmidt, W.; Pichkhadze, K.; Linkin, V.; Vazquez, L.; Uspensky, M.; Polkko, J.; Genzer, M.; Lipatov, A.; Guerrero, H.; Alexashkin, S.; Haukka, H.; Savijarvi, H.; Kauhanen, J.

2008-09-01

We are developing a new kind of planetary exploration mission for Mars - MetNet in situ observation network based on a new semi-hard landing vehicle called the Met-Net Lander (MNL). The eventual scope of the MetNet Mission is to deploy some 20 MNLs on the Martian surface using inflatable descent system structures, which will be supported by observations from the orbit around Mars. Currently we are working on the MetNet Mars Precursor Mission (MMPM) to deploy one MetNet Lander to Mars in the 2009/2011 launch window as a technology and science demonstration mission. The MNL will have a versatile science payload focused on the atmospheric science of Mars. Detailed characterization of the Martian atmospheric circulation patterns, boundary layer phenomena, and climatology cycles, require simultaneous in-situ measurements by a network of observation posts on the Martian surface. The scientific payload of the MetNet Mission encompasses separate instrument packages for the atmospheric entry and descent phase and for the surface operation phase. The MetNet mission concept and key probe technologies have been developed and the critical subsystems have been qualified to meet the Martian environmental and functional conditions. Prototyping of the payload instrumentation with final dimensions was carried out in 2003-2006.This huge development effort has been fulfilled in collaboration between the Finnish Meteorological Institute (FMI), the Russian Lavoschkin Association (LA) and the Russian Space Research Institute (IKI) since August 2001. Currently the INTA (Instituto Nacional de Técnica Aeroespacial) from Spain is also participating in the MetNet payload development. To understand the behavior and dynamics of the Martian atmosphere, a wealth of simultaneous in situ observations are needed on varying types of Martian orography, terrain and altitude spanning all latitudes and longitudes. This will be performed by the Mars MetNet Mission. In addition to the science aspects the

Integral design method for simple and small Mars lander system using membrane aeroshell

Science.gov (United States)

Sakagami, Ryo; Takahashi, Ryohei; Wachi, Akifumi; Koshiro, Yuki; Maezawa, Hiroyuki; Kasai, Yasko; Nakasuka, Shinichi

2018-03-01

To execute Mars surface exploration missions, spacecraft need to overcome the difficulties of the Mars entry, descent, and landing (EDL) sequences. Previous landing missions overcame these challenges with complicated systems that could only be executed by organizations with mature technology and abundant financial resources. In this paper, we propose a novel integral design methodology for a small, simple Mars lander that is achievable even by organizations with limited technology and resources such as universities or emerging countries. We aim to design a lander (including its interplanetary cruise stage) whose size and mass are under 1 m3 and 150 kg, respectively. We adopted only two components for Mars EDL process: a "membrane aeroshell" for the Mars atmospheric entry and descent sequence and one additional mechanism for the landing sequence. The landing mechanism was selected from the following three candidates: (1) solid thrusters, (2) aluminum foam, and (3) a vented airbag. We present a reasonable design process, visualize dependencies among parameters, summarize sizing methods for each component, and propose the way to integrate these components into one system. To demonstrate the effectiveness, we applied this methodology to the actual Mars EDL mission led by the National Institute of Information and Communications Technology (NICT) and the University of Tokyo. As a result, an 80 kg class Mars lander with a 1.75 m radius membrane aeroshell and a vented airbag was designed, and the maximum landing shock that the lander will receive was 115 G.

Entry, Descent and Landing Systems Analysis: Exploration Feed Forward Internal Peer Review Slide Package

Science.gov (United States)

Dwyer Cianciolo, Alicia M. (Editor)

2011-01-01

NASA senior management commissioned the Entry, Descent and Landing Systems Analysis (EDL-SA) Study in 2008 to identify and roadmap the Entry, Descent and Landing (EDL) technology investments that the agency needed to successfully land large payloads at Mars for both robotic and human-scale missions. Year 1 of the study focused on technologies required for Exploration-class missions to land payloads of 10 to 50 mt. Inflatable decelerators, rigid aeroshell and supersonic retro-propulsion emerged as the top candidate technologies. In Year 2 of the study, low TRL technologies identified in Year 1, inflatables aeroshells and supersonic retropropulsion, were combined to create a demonstration precursor robotic mission. This part of the EDL-SA Year 2 effort, called Exploration Feed Forward (EFF), took much of the systems analysis simulation and component model development from Year 1 to the next level of detail.

The Mars Science Laboratory APXS calibration target: Comparison of Martian measurements with the terrestrial calibration

International Nuclear Information System (INIS)

Campbell, J.L.; King, P.L.; Burkemper, L.; Berger, J.A.; Gellert, R.; Boyd, N.I.; Perrett, G.M.; Pradler, I.; Thompson, L.; Edgett, K.S.; Yingst, R.A.

2014-01-01

The Mars Science Laboratory Curiosity rover carries a basalt calibration target for monitoring the performance of the alpha particle X-ray spectrometer. The spectrum acquired on Sol 34 shows increased contributions from Mg, S, Cl and Fe relative to laboratory spectra recorded before launch. Mars Hand Lens Imager images confirm changes in the appearance of the surface. Spectra taken on Sols 179 and 411 indicate some loss of the deposited material. The observations suggest deposition of a surface film likely consisting of dust mobilized by impingement of the sky crane’s terminal descent engine plumes with surface fines during Curiosity’s landing. New APXS software has been used to model the thin film that coated the calibration target on landing. The results suggest that a film of about 100 nm thickness, and containing predominantly MgO, Fe 2 O 3 , SO 3 , Cl and Na 2 O could give rise to the observed spectral changes. If this film is also present on the alpha particle sources within the APXS, then its effect is negligible and the terrestrial calibration remains appropriate

Stochastic parallel gradient descent based adaptive optics used for a high contrast imaging coronagraph

International Nuclear Information System (INIS)

Dong Bing; Ren Deqing; Zhang Xi

2011-01-01

An adaptive optics (AO) system based on a stochastic parallel gradient descent (SPGD) algorithm is proposed to reduce the speckle noises in the optical system of a stellar coronagraph in order to further improve the contrast. The principle of the SPGD algorithm is described briefly and a metric suitable for point source imaging optimization is given. The feasibility and good performance of the SPGD algorithm is demonstrated by an experimental system featured with a 140-actuator deformable mirror and a Hartmann-Shark wavefront sensor. Then the SPGD based AO is applied to a liquid crystal array (LCA) based coronagraph to improve the contrast. The LCA can modulate the incoming light to generate a pupil apodization mask of any pattern. A circular stepped pattern is used in our preliminary experiment and the image contrast shows improvement from 10 -3 to 10 -4.5 at an angular distance of 2λ/D after being corrected by SPGD based AO.

One Mars year: viking lander imaging observations.

Science.gov (United States)

Jones, K L; Arvidson, R E; Guinness, E A; Bragg, S L; Wall, S D; Carlston, C E; Pidek, D G

1979-05-25

Throughout the complete Mars year during which they have been on the planet, the imaging systems aboard the two Viking landers have documented a variety of surface changes. Surface condensates, consisting of both solid H(2)O and CO(2), formed at the Viking 2 lander site during the winter. Additional observations suggest that surface erosion rates due to dust redistribution may be substantially less than those predicted on the basis of pre-Viking observations. The Viking 1 lander will continue to acquire and transmit a predetermined sequence of imaging and meteorology data as long as it is operative.

The imaging performance of the SRC on Mars Express

Science.gov (United States)

Oberst, J.; Schwarz, G.; Behnke, T.; Hoffmann, H.; Matz, K.-D.; Flohrer, J.; Hirsch, H.; Roatsch, T.; Scholten, F.; Hauber, E.; Brinkmann, B.; Jaumann, R.; Williams, D.; Kirk, R.; Duxbury, T.; Leu, C.; Neukum, G.

2008-01-01

The Mars Express spacecraft carries the pushbroom scanner high-resolution stereo camera (HRSC) and its added imaging subsystem super resolution channel (SRC). The SRC is equipped with its own optical system and a 1024??1024 framing sensor. SRC produces snapshots with 2.3 m ground pixel size from the nominal spacecraft pericenter height of 250 km, which are typically embedded in the central part of the large HRSC scenes. The salient features of the SRC are its light-weight optics, a reliable CCD detector, and high-speed read-out electronics. The quality and effective visibility of details in the SRC images unfortunately falls short of what has been expected. In cases where thermal balance cannot be reached, artifacts, such as blurring and "ghost features" are observed in the images. In addition, images show large numbers of blemish pixels and are plagued by electronic noise. As a consequence, we have developed various image improving algorithms, which are discussed in this paper. While results are encouraging, further studies of image restoration by dedicated processing appear worthwhile. The SRC has obtained more than 6940 images at the time of writing (1 September 2007), which often show fascinating details in surface morphology. SRC images are highly useful for a variety of applications in planetary geology, for studies of the Mars atmosphere, and for astrometric observations of the Martian satellites. This paper will give a full account of the design philosophy, technical concept, calibration, operation, integration with HRSC, and performance, as well as science accomplishments of the SRC. ?? 2007 Elsevier Ltd. All rights reserved.

Sedimentological Investigations of the Martian Surface using the Mars 2001 Robotic Arm Camera and MECA Optical Microscope

Science.gov (United States)

Rice, J. W., Jr.; Smith, P. H.; Marshall, J. R.

1999-01-01

The first microscopic sedimentological studies of the Martian surface will commence with the landing of the Mars Polar Lander (MPL) December 3, 1999. The Robotic Arm Camera (RAC) has a resolution of 25 um/p which will permit detailed micromorphological analysis of surface and subsurface materials. The Robotic Ann will be able to dig up to 50 cm below the surface. The walls of the trench will also be inspected by RAC to look for evidence of stratigraphic and / or sedimentological relationships. The 2001 Mars Lander will build upon and expand the sedimentological research begun by the RAC on MPL. This will be accomplished by: (1) Macroscopic (dm to cm): Descent Imager, Pancam, RAC; (2) Microscopic (mm to um RAC, MECA Optical Microscope (Figure 2), AFM This paper will focus on investigations that can be conducted by the RAC and MECA Optical Microscope.

Entry, Descent and Landing Systems Analysis Study: Phase 2 Report on Exploration Feed-Forward Systems

Science.gov (United States)

Dwyer Ciancolo, Alicia M.; Davis, Jody L.; Engelund, Walter C.; Komar, D. R.; Queen, Eric M.; Samareh, Jamshid A.; Way, David W.; Zang, Thomas A.; Murch, Jeff G.; Krizan, Shawn A.;

Mars entry-to-landing trajectory optimization and closed loop guidance

Science.gov (United States)

Ilgen, Marc R.; Manning, Raymund A.; Cruz, Manuel I.

1991-01-01

The guidance strategy of the Mars Rover Sample Return mission is presented in detail. Aeromaneuver versus aerobrake trades are examined, and an aerobrake analysis is presented which takes into account targeting, guidance, flight control, trajectory profile, delivery accuracy. An aeromaneuver analysis is given which includes the entry corridor, maneuver footprint, guidance, preentry phase, constant drag phase, equilibrium guide phase, variable drag phase, influence of trajectory profile on the entry flight loads, parachute deployment conditions and strategies, and landing accuracy. The Mars terminal descent phase is analyzed.

Regression Analysis of Top of Descent Location for Idle-thrust Descents

Science.gov (United States)

Stell, Laurel; Bronsvoort, Jesper; McDonald, Greg

2013-01-01

In this paper, multiple regression analysis is used to model the top of descent (TOD) location of user-preferred descent trajectories computed by the flight management system (FMS) on over 1000 commercial flights into Melbourne, Australia. The independent variables cruise altitude, final altitude, cruise Mach, descent speed, wind, and engine type were also recorded or computed post-operations. Both first-order and second-order models are considered, where cross-validation, hypothesis testing, and additional analysis are used to compare models. This identifies the models that should give the smallest errors if used to predict TOD location for new data in the future. A model that is linear in TOD altitude, final altitude, descent speed, and wind gives an estimated standard deviation of 3.9 nmi for TOD location given the trajec- tory parameters, which means about 80% of predictions would have error less than 5 nmi in absolute value. This accuracy is better than demonstrated by other ground automation predictions using kinetic models. Furthermore, this approach would enable online learning of the model. Additional data or further knowl- edge of algorithms is necessary to conclude definitively that no second-order terms are appropriate. Possible applications of the linear model are described, including enabling arriving aircraft to fly optimized descents computed by the FMS even in congested airspace. In particular, a model for TOD location that is linear in the independent variables would enable decision support tool human-machine interfaces for which a kinetic approach would be computationally too slow.

Relay Telecommunications for the Coming Decade of Mars Exploration

Science.gov (United States)

Edwards, C.; DePaula, R.

2010-01-01

Over the past decade, an evolving network of relay-equipped orbiters has advanced our capabilities for Mars exploration. NASA's Mars Global Surveyor, 2001 Mars Odyssey, and Mars Reconnaissance Orbiter (MRO), as well as ESA's Mars Express Orbiter, have provided telecommunications relay services to the 2003 Mars Exploration Rovers, Spirit and Opportunity, and to the 2007 Phoenix Lander. Based on these successes, a roadmap for continued Mars relay services is in place for the coming decade. MRO and Odyssey will provide key relay support to the 2011 Mars Science Laboratory (MSL) mission, including capture of critical event telemetry during entry, descent, and landing, as well as support for command and telemetry during surface operations, utilizing new capabilities of the Electra relay payload on MRO and the Electra-Lite payload on MSL to allow significant increase in data return relative to earlier missions. Over the remainder of the decade a number of additional orbiter and lander missions are planned, representing new orbital relay service providers and new landed relay users. In this paper we will outline this Mars relay roadmap, quantifying relay performance over time, illustrating planned support scenarios, and identifying key challenges and technology infusion opportunities.

Telecommunications Relay Support of the Mars Phoenix Lander Mission

Science.gov (United States)

Edwards, Charles D., Jr.; Erickson, James K.; Gladden, Roy E.; Guinn, Joseph R.; Ilott, Peter A.; Jai, Benhan; Johnston, Martin D.; Kornfeld, Richard P.; Martin-Mur, Tomas J.; McSmith, Gaylon W.;

Limb clouds and dust on Mars from images obtained by the Visual Monitoring Camera (VMC) onboard Mars Express

Science.gov (United States)

Sánchez-Lavega, A.; Chen-Chen, H.; Ordoñez-Etxeberria, I.; Hueso, R.; del Río-Gaztelurrutia, T.; Garro, A.; Cardesín-Moinelo, A.; Titov, D.; Wood, S.

2018-01-01

The Visual Monitoring Camera (VMC) onboard the Mars Express (MEx) spacecraft is a simple camera aimed to monitor the release of the Beagle-2 lander on Mars Express and later used for public outreach. Here, we employ VMC as a scientific instrument to study and characterize high altitude aerosols events (dust and condensates) observed at the Martian limb. More than 21,000 images taken between 2007 and 2016 have been examined to detect and characterize elevated layers of dust in the limb, dust storms and clouds. We report a total of 18 events for which we give their main properties (areographic location, maximum altitude, limb projected size, Martian solar longitude and local time of occurrence). The top altitudes of these phenomena ranged from 40 to 85 km and their horizontal extent at the limb ranged from 120 to 2000 km. They mostly occurred at Equatorial and Tropical latitudes (between ∼30°N and 30°S) at morning and afternoon local times in the southern fall and northern winter seasons. None of them are related to the orographic clouds that typically form around volcanoes. Three of these events have been studied in detail using simultaneous images taken by the MARCI instrument onboard Mars Reconnaissance Orbiter (MRO) and studying the properties of the atmosphere using the predictions from the Mars Climate Database (MCD) General Circulation Model. This has allowed us to determine the three-dimensional structure and nature of these events, with one of them being a regional dust storm and the two others water ice clouds. Analyses based on MCD and/or MARCI images for the other cases studied indicate that the rest of the events correspond most probably to water ice clouds.

The early thermal evolution of Mars

Science.gov (United States)

Bhatia, G. K.; Sahijpal, S.

2016-01-01

Hf-W isotopic systematics of Martian meteorites have provided evidence for the early accretion and rapid core formation of Mars. We present the results of numerical simulations performed to study the early thermal evolution and planetary scale differentiation of Mars. The simulations are confined to the initial 50 Myr (Ma) of the formation of solar system. The accretion energy produced during the growth of Mars and the decay energy due to the short-lived radio-nuclides 26Al, 60Fe, and the long-lived nuclides, 40K, 235U, 238U, and 232Th are incorporated as the heat sources for the thermal evolution of Mars. During the core-mantle differentiation of Mars, the molten metallic blobs were numerically moved using Stoke's law toward the center with descent velocity that depends on the local acceleration due to gravity. Apart from the accretion and the radioactive heat energies, the gravitational energy produced during the differentiation of Mars and the associated heat transfer is also parametrically incorporated in the present work to make an assessment of its contribution to the early thermal evolution of Mars. We conclude that the accretion energy alone cannot produce widespread melting and differentiation of Mars even with an efficient consumption of the accretion energy. This makes 26Al the prime source for the heating and planetary scale differentiation of Mars. We demonstrate a rapid accretion and core-mantle differentiation of Mars within the initial ~1.5 Myr. This is consistent with the chronological records of Martian meteorites.

Science Applications of a Multispectral Microscopic Imager for the Astrobiological Exploration of Mars

Science.gov (United States)

Farmer, Jack D.; Sellar, R. Glenn; Swayze, Gregg A.; Blaney, Diana L.

2014-01-01

Abstract Future astrobiological missions to Mars are likely to emphasize the use of rovers with in situ petrologic capabilities for selecting the best samples at a site for in situ analysis with onboard lab instruments or for caching for potential return to Earth. Such observations are central to an understanding of the potential for past habitable conditions at a site and for identifying samples most likely to harbor fossil biosignatures. The Multispectral Microscopic Imager (MMI) provides multispectral reflectance images of geological samples at the microscale, where each image pixel is composed of a visible/shortwave infrared spectrum ranging from 0.46 to 1.73 μm. This spectral range enables the discrimination of a wide variety of rock-forming minerals, especially Fe-bearing phases, and the detection of hydrated minerals. The MMI advances beyond the capabilities of current microimagers on Mars by extending the spectral range into the infrared and increasing the number of spectral bands. The design employs multispectral light-emitting diodes and an uncooled indium gallium arsenide focal plane array to achieve a very low mass and high reliability. To better understand and demonstrate the capabilities of the MMI for future surface missions to Mars, we analyzed samples from Mars-relevant analog environments with the MMI. Results indicate that the MMI images faithfully resolve the fine-scale microtextural features of samples and provide important information to help constrain mineral composition. The use of spectral endmember mapping reveals the distribution of Fe-bearing minerals (including silicates and oxides) with high fidelity, along with the presence of hydrated minerals. MMI-based petrogenetic interpretations compare favorably with laboratory-based analyses, revealing the value of the MMI for future in situ rover-mediated astrobiological exploration of Mars. Key Words: Mars—Microscopic imager—Multispectral imaging�

Science applications of a multispectral microscopic imager for the astrobiological exploration of Mars

Science.gov (United States)

Nunez, Jorge; Farmer, Jack; Sellar, R. Glenn; Swayze, Gregg A.; Blaney, Diana L.

2014-01-01

Future astrobiological missions to Mars are likely to emphasize the use of rovers with in situ petrologic capabilities for selecting the best samples at a site for in situ analysis with onboard lab instruments or for caching for potential return to Earth. Such observations are central to an understanding of the potential for past habitable conditions at a site and for identifying samples most likely to harbor fossil biosignatures. The Multispectral Microscopic Imager (MMI) provides multispectral reflectance images of geological samples at the microscale, where each image pixel is composed of a visible/shortwave infrared spectrum ranging from 0.46 to 1.73 μm. This spectral range enables the discrimination of a wide variety of rock-forming minerals, especially Fe-bearing phases, and the detection of hydrated minerals. The MMI advances beyond the capabilities of current microimagers on Mars by extending the spectral range into the infrared and increasing the number of spectral bands. The design employs multispectral light-emitting diodes and an uncooled indium gallium arsenide focal plane array to achieve a very low mass and high reliability. To better understand and demonstrate the capabilities of the MMI for future surface missions to Mars, we analyzed samples from Mars-relevant analog environments with the MMI. Results indicate that the MMI images faithfully resolve the fine-scale microtextural features of samples and provide important information to help constrain mineral composition. The use of spectral endmember mapping reveals the distribution of Fe-bearing minerals (including silicates and oxides) with high fidelity, along with the presence of hydrated minerals. MMI-based petrogenetic interpretations compare favorably with laboratory-based analyses, revealing the value of the MMI for future in situ rover-mediated astrobiological exploration of Mars.

The Mars Science Laboratory APXS calibration target: Comparison of Martian measurements with the terrestrial calibration

Energy Technology Data Exchange (ETDEWEB)

Campbell, J.L., E-mail: icampbel@uoguelph.ca [Guelph-Waterloo Physics Institute, University of Guelph, Ontario N1G2W1 (Canada); King, P.L. [Guelph-Waterloo Physics Institute, University of Guelph, Ontario N1G2W1 (Canada); Institute of Meteoritics, University of New Mexico, NM 87131 (United States); Department of Earth Sciences, Western University, London, Ontario N6A3K7 (Canada); Burkemper, L. [Institute of Meteoritics, University of New Mexico, NM 87131 (United States); Berger, J.A. [Institute of Meteoritics, University of New Mexico, NM 87131 (United States); Department of Earth Sciences, Western University, London, Ontario N6A3K7 (Canada); Gellert, R.; Boyd, N.I.; Perrett, G.M.; Pradler, I. [Guelph-Waterloo Physics Institute, University of Guelph, Ontario N1G2W1 (Canada); Thompson, L. [Planetary and Space Science Centre, University of New Brunswick, Fredericton, NB E3B5A3 (Canada); Edgett, K.S. [Malin Space Science Systems, San Diego, CA 92191-0148 (United States); Yingst, R.A. [Planetary Science Institute, Tucson, AZ 85719-2395 (United States)

2014-03-15

The Mars Science Laboratory Curiosity rover carries a basalt calibration target for monitoring the performance of the alpha particle X-ray spectrometer. The spectrum acquired on Sol 34 shows increased contributions from Mg, S, Cl and Fe relative to laboratory spectra recorded before launch. Mars Hand Lens Imager images confirm changes in the appearance of the surface. Spectra taken on Sols 179 and 411 indicate some loss of the deposited material. The observations suggest deposition of a surface film likely consisting of dust mobilized by impingement of the sky crane’s terminal descent engine plumes with surface fines during Curiosity’s landing. New APXS software has been used to model the thin film that coated the calibration target on landing. The results suggest that a film of about 100 nm thickness, and containing predominantly MgO, Fe{sub 2}O{sub 3}, SO{sub 3}, Cl and Na{sub 2}O could give rise to the observed spectral changes. If this film is also present on the alpha particle sources within the APXS, then its effect is negligible and the terrestrial calibration remains appropriate.

Human missions to Mars enabling technologies for exploring the red planet

CERN Document Server

Rapp, Donald

2016-01-01

A mission to send humans to explore the surface of Mars has been the ultimate goal of planetary exploration since the 1950s, when von Braun conjectured a flotilla of 10 interplanetary vessels carrying a crew of at least 70 humans. Since then, more than 1,000 studies were carried out on human missions to Mars, but after 60 years of study, we remain in the early planning stages. The second edition of this book now includes an annotated history of Mars mission studies, with quantitative data wherever possible. Retained from the first edition, Donald Rapp looks at human missions to Mars from an engineering perspective. He divides the mission into a number of stages: Earth’s surface to low-Earth orbit (LEO); departing from LEO toward Mars; Mars orbit insertion and entry, descent and landing; ascent from Mars; trans-Earth injection from Mars orbit and Earth return. For each segment, he analyzes requirements for candidate technologies. In this connection, he discusses the status and potential of a wide range of el...

Mars Orbiter Camera Views the 'Face on Mars' - Best View from Viking

Science.gov (United States)

1998-01-01

Shortly after midnight Sunday morning (5 April 1998 12:39 AM PST), the Mars Orbiter Camera (MOC) on the Mars Global Surveyor (MGS) spacecraft successfully acquired a high resolution image of the 'Face on Mars' feature in the Cydonia region. The image was transmitted to Earth on Sunday, and retrieved from the mission computer data base Monday morning (6 April 1998). The image was processed at the Malin Space Science Systems (MSSS) facility 9:15 AM and the raw image immediately transferred to the Jet Propulsion Laboratory (JPL) for release to the Internet. The images shown here were subsequently processed at MSSS.The picture was acquired 375 seconds after the spacecraft's 220th close approach to Mars. At that time, the 'Face', located at approximately 40.8o N, 9.6o W, was 275 miles (444 km) from the spacecraft. The 'morning' sun was 25o above the horizon. The picture has a resolution of 14.1 feet (4.3 meters) per pixel, making it ten times higher resolution than the best previous image of the feature, which was taken by the Viking Mission in the mid-1970's. The full image covers an area 2.7 miles (4.4 km) wide and 25.7 miles (41.5 km) long.This Viking Orbiter image is one of the best Viking pictures of the area Cydonia where the 'Face' is located. Marked on the image are the 'footprint' of the high resolution (narrow angle) Mars Orbiter Camera image and the area seen in enlarged views (dashed box). See PIA01440-1442 for these images in raw and processed form.Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Building Virtual Mars

Science.gov (United States)

Abercrombie, S. P.; Menzies, A.; Goddard, C.

2017-12-01

Virtual and augmented reality enable scientists to visualize environments that are very difficult, or even impossible to visit, such as the surface of Mars. A useful immersive visualization begins with a high quality reconstruction of the environment under study. This presentation will discuss a photogrammetry pipeline developed at the Jet Propulsion Laboratory to reconstruct 3D models of the surface of Mars using stereo images sent back to Earth by the Curiosity Mars rover. The resulting models are used to support a virtual reality tool (OnSight) that allows scientists and engineers to visualize the surface of Mars as if they were standing on the red planet. Images of Mars present challenges to existing scene reconstruction solutions. Surface images of Mars are sparse with minimal overlap, and are often taken from extremely different viewpoints. In addition, the specialized cameras used by Mars rovers are significantly different than consumer cameras, and GPS localization data is not available on Mars. This presentation will discuss scene reconstruction with an emphasis on coping with limited input data, and on creating models suitable for rendering in virtual reality at high frame rate.

Curiosity's Mars Hand Lens Imager (MAHLI): Inital Observations and Activities

Science.gov (United States)

Edgett, K. S.; Yingst, R. A.; Minitti, M. E.; Robinson, M. L.; Kennedy, M. R.; Lipkaman, L. J.; Jensen, E. H.; Anderson, R. C.; Bean, K. M.; Beegle, L. W.;

Microscope on Mars

Science.gov (United States)

2004-01-01

This image taken at Meridiani Planum, Mars by the panoramic camera on the Mars Exploration Rover Opportunity shows the rover's microscopic imager (circular device in center), located on its instrument deployment device, or 'arm.' The image was acquired on the ninth martian day or sol of the rover's mission.

Iterative metal artefact reduction (MAR) in postsurgical chest CT: comparison of three iMAR-algorithms.

Science.gov (United States)

Aissa, Joel; Boos, Johannes; Sawicki, Lino Morris; Heinzler, Niklas; Krzymyk, Karl; Sedlmair, Martin; Kröpil, Patric; Antoch, Gerald; Thomas, Christoph

2017-11-01

The purpose of this study was to evaluate the impact of three novel iterative metal artefact (iMAR) algorithms on image quality and artefact degree in chest CT of patients with a variety of thoracic metallic implants. 27 postsurgical patients with thoracic implants who underwent clinical chest CT between March and May 2015 in clinical routine were retrospectively included. Images were retrospectively reconstructed with standard weighted filtered back projection (WFBP) and with three iMAR algorithms (iMAR-Algo1 = Cardiac algorithm, iMAR-Algo2 = Pacemaker algorithm and iMAR-Algo3 = ThoracicCoils algorithm). The subjective and objective image quality was assessed. Averaged over all artefacts, artefact degree was significantly lower for the iMAR-Algo1 (58.9 ± 48.5 HU), iMAR-Algo2 (52.7 ± 46.8 HU) and the iMAR-Algo3 (51.9 ± 46.1 HU) compared with WFBP (91.6 ± 81.6 HU, p algorithms, respectively. iMAR-Algo2 and iMAR-Algo3 reconstructions decreased mild and moderate artefacts compared with WFBP and iMAR-Algo1 (p algorithms led to a significant reduction of metal artefacts and increase in overall image quality compared with WFBP in chest CT of patients with metallic implants in subjective and objective analysis. The iMARAlgo2 and iMARAlgo3 were best for mild artefacts. IMARAlgo1 was superior for severe artefacts. Advances in knowledge: Iterative MAR led to significant artefact reduction and increase image-quality compared with WFBP in CT after implementation of thoracic devices. Adjusting iMAR-algorithms to patients' metallic implants can help to improve image quality in CT.

EU-FP7-iMars: Analysis of Mars Multi-Resolution Images using Auto-Coregistration, Data Mining and Crowd Source Techniques

Science.gov (United States)

Ivanov, Anton; Oberst, Jürgen; Yershov, Vladimir; Muller, Jan-Peter; Kim, Jung-Rack; Gwinner, Klaus; Van Gasselt, Stephan; Morley, Jeremy; Houghton, Robert; Bamford, Steven; Sidiropoulos, Panagiotis

Understanding the role of different planetary surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 15 years, especially in 3D imaging of surface shape. This has led to the ability to be able to overlay different epochs back to the mid-1970s, examine time-varying changes (such as the recent discovery of boulder movement, tracking inter-year seasonal changes and looking for occurrences of fresh craters. Consequently we are seeing a dramatic improvement in our understanding of surface formation processes. Since January 2004, the ESA Mars Express has been acquiring global data, especially HRSC stereo (12.5-25 m nadir images) with 87% coverage with more than 65% useful for stereo mapping. NASA began imaging the surface of Mars, initially from flybys in the 1960s and then from the first orbiter with image resolution less than 100 m in the late 1970s from Viking Orbiter. The most recent orbiter, NASA MRO, has acquired surface imagery of around 1% of the Martian surface from HiRISE (at ≈20 cm) and ≈5% from CTX (≈6 m) in stereo. Within the iMars project (http://i-Mars.eu), a fully automated large-scale processing (“Big Data”) solution is being developed to generate the best possible multi-resolution DTM of Mars. In addition, HRSC OrthoRectified Images (ORI) will be used as a georeference basis so that all higher resolution ORIs will be co-registered to the HRSC DTMs (50-100m grid) products generated at DLR and, from CTX (6-20 m grid) and HiRISE (1-3 m grids) on a large-scale Linux cluster based at MSSL. The HRSC products will be employed to provide a geographic reference for all current, future and historical NASA products using automated co-registration based on feature points and initial results will be shown here. In 2015, many of the entire NASA and ESA orbital images will be co-registered and the updated georeferencing

Imaging the Extended Hot Hydrogen Exosphere at Mars to Determine the Water Escape Rate

Science.gov (United States)

Bhattacharyya, Dolon

2017-08-01

ACS SBC imaging of the extended hydrogen exosphere of Mars is proposed to identify the hot hydrogen population present in the exosphere of Mars. Determining the characteristics of this population and the underlying processes responsible for its production are critical towards constraining the escape flux of H from Mars, which in turn is directly related to the water escape history of Mars. Since the hot atoms appear mainly at high altitudes, these observations will be scheduled when Mars is far from Earth allowing us to image the hot hydrogen atoms at high altitudes where they dominate the population. The altitude coverage by HST will extend beyond 30,000 km or 8.8 Martian radii in this case, which makes it perfect for this study as orbiting spacecraft remain at low altitudes (MAVEN apoapse is 6000 km) and cannot separate hot atoms from the thermal population at those altitudes. The observations will also be carried out when Mars is near aphelion, the atmospheric temperature is low, and the thermal population has a small scale height, allowing the clear characterization of the hot hydrogen layer. Another advantage of conducting this study in this cycle is that the solar activity is near its minimum, allowing us to discriminate between changes in the hot hydrogen population from processes taking place within the atmosphere of Mars and changes due to external drivers like the solar wind, producing this non-thermal population. This proposal is part of the HST UV initiative.

Sustaining Human Presence on Mars Using ISRU and a Reusable Lander

Science.gov (United States)

Arney, Dale C.; Jones, Christopher A.; Klovstad, Jordan J.; Komar, D.R.; Earle, Kevin; Moses, Robert; Shyface, Hilary R.

2015-01-01

This paper presents an analysis of the impact of ISRU (In-Site Resource Utilization), reusability, and automation on sustaining a human presence on Mars, requiring a transition from Earth dependence to Earth independence. The study analyzes the surface and transportation architectures and compared campaigns that revealed the importance of ISRU and reusability. A reusable Mars lander, Hercules, eliminates the need to deliver a new descent and ascent stage with each cargo and crew delivery to Mars, reducing the mass delivered from Earth. As part of an evolvable transportation architecture, this investment is key to enabling continuous human presence on Mars. The extensive use of ISRU reduces the logistics supply chain from Earth in order to support population growth at Mars. Reliable and autonomous systems, in conjunction with robotics, are required to enable ISRU architectures as systems must operate and maintain themselves while the crew is not present. A comparison of Mars campaigns is presented to show the impact of adding these investments and their ability to contribute to sustaining a human presence on Mars.

'Mars-shine'

Science.gov (United States)

2005-01-01

[figure removed for brevity, see original site] 'Mars-shine' Composite NASA's Mars Exploration Rover Spirit continues to take advantage of favorable solar power conditions to conduct occasional nighttime astronomical observations from the summit region of 'Husband Hill.' Spirit has been observing the martian moons Phobos and Deimos to learn more about their orbits and surface properties. This has included observing eclipses. On Earth, a solar eclipse occurs when the Moon's orbit takes it exactly between the Sun and Earth, casting parts of Earth into shadow. A lunar eclipse occurs when the Earth is exactly between the Sun and the Moon, casting the Moon into shadow and often giving it a ghostly orange-reddish color. This color is created by sunlight reflected through Earth's atmosphere into the shadowed region. The primary difference between terrestrial and martian eclipses is that Mars' moons are too small to completely block the Sun from view during solar eclipses. Recently, Spirit observed a 'lunar' eclipse on Mars. Phobos, the larger of the two martian moons, was photographed while slipping into the shadow of Mars. Jim Bell, the astronomer in charge of the rover's panoramic camera (Pancam), suggested calling it a 'Phobal' eclipse rather than a lunar eclipse as a way of identifying which of the dozens of moons in our solar system was being cast into shadow. With the help of the Jet Propulsion Laboratory's navigation team, the Pancam team planned instructions to Spirit for acquiring the views shown here of Phobos as it entered into a lunar eclipse on the evening of the rover's 639th martian day, or sol (Oct. 20, 2005) on Mars. This image is a time-lapse composite of eight Pancam images of Phobos moving across the martian sky. The entire eclipse lasted more than 26 minutes, but Spirit was able to observe only in the first 15 minutes. During the time closest to the shadow crossing, Spirit's cameras were programmed to take images every 10 seconds. In the first three

EU-FP7-iMARS: analysis of Mars multi-resolution images using auto-coregistration, data mining and crowd source techniques: A Mid-term Report

Science.gov (United States)

Muller, J.-P.; Yershov, V.; Sidiropoulos, P.; Gwinner, K.; Willner, K.; Fanara, L.; Waelisch, M.; van Gasselt, S.; Walter, S.; Ivanov, A.; Cantini, F.; Morley, J. G.; Sprinks, J.; Giordano, M.; Wardlaw, J.; Kim, J.-R.; Chen, W.-T.; Houghton, R.; Bamford, S.

2015-10-01

Understanding the role of different solid surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 8 years, especially in 3D imaging of surface shape (down to resolutions of 10s of cms) and subsequent terrain correction of imagery from orbiting spacecraft. This has led to the potential to be able to overlay different epochs back to the mid-1970s. Within iMars, a processing system has been developed to generate 3D Digital Terrain Models (DTMs) and corresponding OrthoRectified Images (ORIs) fully automatically from NASA MRO HiRISE and CTX stereo-pairs which are coregistered to corresponding HRSC ORI/DTMs. In parallel, iMars has developed a fully automated processing chain for co-registering level-1 (EDR) images from all previous NASA orbital missions to these HRSC ORIs and in the case of HiRISE these are further co-registered to previously co-registered CTX-to-HRSC ORIs. Examples will be shown of these multi-resolution ORIs and the application of different data mining algorithms to change detection using these co-registered images. iMars has recently launched a citizen science experiment to evaluate best practices for future citizen scientist validation of such data mining processed results. An example of the iMars website will be shown along with an embedded Version 0 prototype of a webGIS based on OGC standards.

Present Status and Near Term Activities for the ExoMars Trace Gas Orbiter.

Science.gov (United States)

Svedhem, H.; Vago, J. L.

2017-12-01

The ExoMars 2016 mission was launched on a Proton rocket from Baikonur, Kazakhstan, on 14 March 2016 and arrived at Mars on 19 October 2016. The spacecraft is now performing aerobraking to reduce its orbital period from initial post-insertion orbital period of one Sol to the final science orbit with a 2 hours period. The orbital inclination will be 74 degrees. During the aerobraking a wealth of data has been acquired on the state of the atmosphere along the tracks between 140km and the lowest altitude at about 105 km. These data are now being analysed and compared with existing models. In average TGO measures a lower atmospheric density than predicted, but the numbers lay within the expected variability. ExoMars is a joint programme of the European Space Agency (ESA) and Roscosmos, Russia. It consists of the ExoMars 2016 mission with the Trace Gas Orbiter, TGO, and the Entry Descent and Landing Demonstrator, EDM, named Schiaparelli, and the ExoMars 2020 mission, which carries a lander and a rover. The TGO scientific payload consists of four instruments: ACS and NOMAD, both infrared spectrometers for atmospheric measurements in solar occultation mode and in nadir mode, CASSIS, a multichannel camera with stereo imaging capability, and FREND, an epithermal neutron detector to search for subsurface hydrogen (as proxy for water ice and hydrated minerals). The launch mass of the TGO was 3700 kg, including fuel. In addition to its scientific measurements TGO will act as a relay orbiter for NASA's landers on Mars and as from 2021 for the ESA-Roscosmos Rover and Surface Station.

Reconnaissance Imaging Spectrometer for Mars CRISM Data Analysis

Science.gov (United States)

Frink, K.; Hayden, D.; Lecompte, D.

2009-05-01

The Compact Reconnaissance Imaging Spectrometer for Mars CRISM (CRISM) carried aboard the Mars Reconnaissance Orbiter (MRO), is the first visible-infrared spectrometer to fly on a NASA Mars mission. CRISM scientists are using the instrument to look for the residue of minerals that form in the presence of water: the 'fingerprints' left by evaporated hot springs, thermal vents, lakes or ponds. With unprecedented clarity, CRISM is mapping regions on the Martian surface at scales as small as 60 feet (about 18 meters) across, when the spacecraft is 186 miles (300 kilometers) above the planet. CRISM is reading 544 'colors' in reflected sunlight to detect certain minerals on the surface, including signature traces of past water. CRISM alone will generate more than 10 terabytes of data, enough to fill more than 15,000 compact discs. Given that quantity of data being returned by MRO-CRISM, this project partners with Johns Hopkins University (JHU) Applied Physics Laboratory (APL) scientists of the CRISM team to assist in the data analysis process. The CRISM operations team has prototyped and will provide the necessary software analysis tools. In addition, the CRISM operations team will provide reduced data volume representations of the data as PNG files, accessible via a web interface without recourse to specialized user tools. The web interface allows me to recommend repeating certain of the CRISM observations as survey results indicate, and to enter notes on the features present in the images. After analysis of a small percentage of CRISM observations, APL scientists concluded that their efforts would be greatly facilitated by adding a preliminary survey to evaluate the overall characteristics and quality of the CRISM data. The first-look should increase the efficiency and speed of their data analysis efforts. This project provides first-look assessments of the data quality while noting features of interest likely to need further study or additional CRISM observations. The

Theseus' arid Peirithoos' descent into the underworld

NARCIS (Netherlands)

Bremmer, Jan N.

2015-01-01

In my contribution I will first briefly discuss the earliest known literary descent, that by Enkidu, which almost certainly influenced the poet of the Odyssey in his depiction of Odysseus' descent. Then I will take a brief look at some descents in the Archaic Age, in particular the earliest

EU-FP7-iMARS: analysis of Mars multi-resolution images using auto-coregistration, data mining and crowd source techniques

Science.gov (United States)

Ivanov, Anton; Muller, Jan-Peter; Tao, Yu; Kim, Jung-Rack; Gwinner, Klaus; Van Gasselt, Stephan; Morley, Jeremy; Houghton, Robert; Bamford, Steven; Sidiropoulos, Panagiotis; Fanara, Lida; Waenlish, Marita; Walter, Sebastian; Steinkert, Ralf; Schreiner, Bjorn; Cantini, Federico; Wardlaw, Jessica; Sprinks, James; Giordano, Michele; Marsh, Stuart

2016-07-01

Understanding planetary atmosphere-surface and extra-terrestrial-surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 15 years, especially in 3D imaging of surface shape. This has led to the ability to be able to overlay different epochs back in time to the mid 1970s, to examine time-varying changes, such as the recent discovery of mass movement, tracking inter-year seasonal changes and looking for occurrences of fresh craters. Within the EU FP-7 iMars project, UCL have developed a fully automated multi-resolution DTM processing chain, called the Co-registration ASP-Gotcha Optimised (CASP-GO), based on the open source NASA Ames Stereo Pipeline (ASP), which is being applied to the production of planetwide DTMs and ORIs (OrthoRectified Images) from CTX and HiRISE. Alongside the production of individual strip CTX & HiRISE DTMs & ORIs, DLR have processed HRSC mosaics of ORIs and DTMs for complete areas in a consistent manner using photogrammetric bundle block adjustment techniques. A novel automated co-registration and orthorectification chain has been developed and is being applied to level-1 EDR images taken by the 4 NASA orbital cameras since 1976 using the HRSC map products (both mosaics and orbital strips) as a map-base. The project has also included Mars Radar profiles from Mars Express and Mars Reconnaissance Orbiter missions. A webGIS has been developed for displaying this time sequence of imagery and a demonstration will be shown applied to one of the map-sheets. Automated quality control techniques are applied to screen for suitable images and these are extended to detect temporal changes in features on the surface such as mass movements, streaks, spiders, impact craters, CO2 geysers and Swiss Cheese terrain. These data mining techniques are then being employed within a citizen science project within the Zooniverse family

The Unparalleled Systems Engineering of MSL's Backup Entry, Descent, and Landing System: Second Chance

Science.gov (United States)

Roumeliotis, Chris; Grinblat, Jonathan; Reeves, Glenn

2013-01-01

Second Chance (SECC) was a bare bones version of Mars Science Laboratory's (MSL) Entry Descent & Landing (EDL) flight software that ran on Curiosity's backup computer, which could have taken over swiftly in the event of a reset of Curiosity's prime computer, in order to land her safely on Mars. Without SECC, a reset of Curiosity's prime computer would have lead to catastrophic mission failure. Even though a reset of the prime computer never occurred, SECC had the important responsibility as EDL's guardian angel, and this responsibility would not have seen such success without unparalleled systems engineering. This paper will focus on the systems engineering behind SECC: Covering a brief overview of SECC's design, the intense schedule to use SECC as a backup system, the verification and validation of the system's "Do No Harm" mandate, the system's overall functional performance, and finally, its use on the fateful day of August 5th, 2012.

Low Energy Electrons in the Mars Plasma Environment

Science.gov (United States)

Link, Richard

2001-01-01

The ionosphere of Mars is rather poorly understood. The only direct measurements were performed by the Viking 1 and 2 landers in 1976, both of which carried a Retarding Potential Analyzer. The RPA was designed to measure ion properties during the descent, although electron fluxes were estimated from changes in the ion currents. Using these derived low-energy electron fluxes, Mantas and Hanson studied the photoelectron and the solar wind electron interactions with the atmosphere and ionosphere of Mars. Unanswered questions remain regarding the origin of the low-energy electron fluxes in the vicinity of the Mars plasma boundary. Crider, in an analysis of Mars Global Surveyor Magnetometer/Electron Reflectometer measurements, has attributed the formation of the magnetic pile-up boundary to electron impact ionization of exospheric neutral species by solar wind electrons. However, the role of photoelectrons escaping from the lower ionosphere was not determined. In the proposed work, we will examine the role of solar wind and ionospheric photoelectrons in producing ionization in the upper ionosphere of Mars. Low-energy (internal (photoelectron) sources of ionization, and accounts for Auger electron production. The code will be used to analyze Mars Global Surveyor measurements of solar wind and photoelectrons down to altitudes below 200 km in the Mars ionosphere, in order to determine the relative roles of solar wind and escaping photoelectrons in maintaining plasma densities in the region of the Mars plasma boundary.

Curiosity’s robotic arm-mounted Mars Hand Lens Imager (MAHLI): Characterization and calibration status

Science.gov (United States)

Edgett, Kenneth S.; Caplinger, Michael A.; Maki, Justin N.; Ravine, Michael A.; Ghaemi, F. Tony; McNair, Sean; Herkenhoff, Kenneth E.; Duston, Brian M.; Wilson, Reg G.; Yingst, R. Aileen; Kennedy, Megan R.; Minitti, Michelle E.; Sengstacken, Aaron J.; Supulver, Kimberley D.; Lipkaman, Leslie J.; Krezoski, Gillian M.; McBride, Marie J.; Jones, Tessa L.; Nixon, Brian E.; Van Beek, Jason K.; Krysak, Daniel J.; Kirk, Randolph L.

2015-01-01

MAHLI (Mars Hand Lens Imager) is a 2-megapixel, Bayer pattern color CCD camera with a macro lens mounted on a rotatable turret at the end of the 2-meters-long robotic arm aboard the Mars Science Laboratory rover, Curiosity. The camera includes white and longwave ultraviolet LEDs to illuminate targets at night. Onboard data processing services include focus stack merging and data compression. Here we report on the results and status of MAHLI characterization and calibration, covering the pre-launch period from August 2008 through the early months of the extended surface mission through February 2015. Since landing in Gale crater in August 2012, MAHLI has been used for a wide range of science and engineering applications, including distinction among a variety of mafic, siliciclastic sedimentary rocks; investigation of grain-scale rock, regolith, and eolian sediment textures and structures; imaging of the landscape; inspection and monitoring of rover and science instrument hardware concerns; and supporting geologic sample selection, extraction, analysis, delivery, and documentation. The camera has a dust cover and focus mechanism actuated by a single stepper motor. The transparent cover was coated with a thin film of dust during landing, thus MAHLI is usually operated with the cover open. The camera focuses over a range from a working distance of 2.04 cm to infinity; the highest resolution images are at 13.9 µm per pixel; images acquired from 6.9 cm show features at the same scale as the Mars Exploration Rover Microscopic Imagers at 31 µm/pixel; and 100 µm/pixel is achieved at a working distance of ~26.5 cm. The very highest resolution images returned from Mars permit distinction of high contrast silt grains in the 30–40 µm size range. MAHLI has performed well; the images need no calibration in order to achieve most of the investigation’s science and engineering goals. The positioning and repeatability of robotic arm placement of the MAHLI camera head have

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.

Deployment of a Prototype Plant GFP Imager at the Arthur Clarke Mars Greenhouse of the Haughton Mars Project

Directory of Open Access Journals (Sweden)

Robert J. Ferl

2008-04-01

Full Text Available The use of engineered plants as biosensors has made elegant strides in the past decades, providing keen insights into the health of plants in general and particularly in the nature and cellular location of stress responses. However, most of the analytical procedures involve laboratory examination of the biosensor plants. With the advent of the green fluorescence protein (GFP as a biosensor molecule, it became at least theoretically possible for analyses of gene expression to occur telemetrically, with the gene expression information of the plant delivered to the investigator over large distances simply as properly processed fluorescence images. Spaceflight and other extraterrestrial environments provide unique challenges to plant life, challenges that often require changes at the gene expression level to accommodate adaptation and survival. Having previously deployed transgenic plant biosensors to evaluate responses to orbital spaceflight, we wished to develop the plants and especially the imaging devices required to conduct such experiments robotically, without operator intervention, within extraterrestrial environments. This requires the development of an autonomous and remotely operated plant GFP imaging system and concomitant development of the communications infrastructure to manage dataflow from the imaging device. Here we report the results of deploying a prototype GFP imaging system within the Arthur Clarke Mars Greenhouse (ACMG an autonomously operated greenhouse located within the Haughton Mars Project in the Canadian High Arctic. Results both demonstrate the applicability of the fundamental GFP biosensor technology and highlight the difficulties in collecting and managing telemetric data from challenging deployment environments.

Continuous Descent Operations using Energy Principles

NARCIS (Netherlands)

De Jong, P.M.A.

2014-01-01

During today’s aircraft descents, Air Traf?c Control (ATC) commands aircraft to descend to specific altitudes and directions to maintain separation and spacing from other aircraft. When the aircraft is instructed to maintain an intermediate descent altitude, it requires engine thrust to maintain

Mass balance of Mars' residual south polar cap from CTX images and other data

Science.gov (United States)

Thomas, P. C.; Calvin, W.; Cantor, B.; Haberle, R.; James, P. B.; Lee, S. W.

2016-04-01

Erosion of pits in the residual south polar cap (RSPC) of Mars concurrent with deposition and fluctuating cap boundaries raises questions about the mass balance and long term stability of the cap. Determining a mass balance by measurement of a net gain or loss of atmospheric CO2 by direct pressure measurements (Haberle, R.M. et al. [2014]. Secular climate change on Mars: An update using one Mars year of MSL pressure data. American Geophysical Union (Fall). Abstract 3947), although perhaps the most direct method, has so far given ambiguous results. Estimating volume changes from imaging data faces challenges, and has previously been attempted only in isolated areas of the cap. In this study we use 6 m/pixel Context Imager (CTX) data from Mars year 31 to map all the morphologic units of the RSPC, expand the measurement record of pit erosion rates, and use high resolution images to place limits on vertical changes in the surface of the residual cap. We find the mass balance in Mars years 9-31 to be -6 to +4 km3/♂y, or roughly -0.039% to +0.026% of the mean atmospheric CO2 mass/♂y. The indeterminate sign results chiefly from uncertainty in the amounts of deposition or erosion on the upper surfaces of deposits (as opposed to scarp retreat). Erosion and net deposition in this period appear to be controlled by summertime planetary scale dust events, the largest occurring in MY 9, another, smaller one in MY 28. The rates of erosion and the deposition observed since MY 9 appear to be consistent with the types of deposits and erosional behavior found in most of the residual cap. However, small areas (100 ♂y) of depositional and/or erosional conditions different from those occurring in the period since MY 9, although these environmental differences could be subtle.

Frost on Mars

Science.gov (United States)

2008-01-01

This image shows bluish-white frost seen on the Martian surface near NASA's Phoenix Mars Lander. The image was taken by the lander's Surface Stereo Imager on the 131st Martian day, or sol, of the mission (Oct. 7, 2008). Frost is expected to continue to appear in images as fall, then winter approach Mars' northern plains. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Aerial Deployment and Inflation System for Mars Helium Balloons

Science.gov (United States)

Lachenmeler, Tim; Fairbrother, Debora; Shreves, Chris; Hall, Jeffery, L.; Kerzhanovich, Viktor V.; Pauken, Michael T.; Walsh, Gerald J.; White, Christopher V.

2009-01-01

A method is examined for safely deploying and inflating helium balloons for missions at Mars. The key for making it possible to deploy balloons that are light enough to be buoyant in the thin, Martian atmosphere is to mitigate the transient forces on the balloon that might tear it. A fully inflated Mars balloon has a diameter of 10 m, so it must be folded up for the trip to Mars, unfolded upon arrival, and then inflated with helium gas in the atmosphere. Safe entry into the Martian atmosphere requires the use of an aeroshell vehicle, which protects against severe heating and pressure loads associated with the hypersonic entry flight. Drag decelerates the aeroshell to supersonic speeds, then two parachutes deploy to slow the vehicle down to the needed safe speed of 25 to 35 m/s for balloon deployment. The parachute system descent dynamic pressure must be approximately 5 Pa or lower at an altitude of 4 km or more above the surface.

Flight Management System Execution of Idle-Thrust Descents in Operations

Science.gov (United States)

Stell, Laurel L.

2011-01-01

To enable arriving aircraft to fly optimized descents computed by the flight management system (FMS) in congested airspace, ground automation must accurately predict descent trajectories. To support development of the trajectory predictor and its error models, commercial flights executed idle-thrust descents, and the recorded data includes the target speed profile and FMS intent trajectories. The FMS computes the intended descent path assuming idle thrust after top of descent (TOD), and any intervention by the controllers that alters the FMS execution of the descent is recorded so that such flights are discarded from the analysis. The horizontal flight path, cruise and meter fix altitudes, and actual TOD location are extracted from the radar data. Using more than 60 descents in Boeing 777 aircraft, the actual speeds are compared to the intended descent speed profile. In addition, three aspects of the accuracy of the FMS intent trajectory are analyzed: the meter fix crossing time, the TOD location, and the altitude at the meter fix. The actual TOD location is within 5 nmi of the intent location for over 95% of the descents. Roughly 90% of the time, the airspeed is within 0.01 of the target Mach number and within 10 KCAS of the target descent CAS, but the meter fix crossing time is only within 50 sec of the time computed by the FMS. Overall, the aircraft seem to be executing the descents as intended by the designers of the onboard automation.

Mars Orbiter Camera Views the 'Face on Mars' - Comparison with Viking

Science.gov (United States)

1998-01-01

Shortly after midnight Sunday morning (5 April 1998 12:39 AM PST), the Mars Orbiter Camera (MOC) on the Mars Global Surveyor (MGS) spacecraft successfully acquired a high resolution image of the 'Face on Mars' feature in the Cydonia region. The image was transmitted to Earth on Sunday, and retrieved from the mission computer data base Monday morning (6 April 1998). The image was processed at the Malin Space Science Systems (MSSS) facility 9:15 AM and the raw image immediately transferred to the Jet Propulsion Laboratory (JPL) for release to the Internet. The images shown here were subsequently processed at MSSS.The picture was acquired 375 seconds after the spacecraft's 220th close approach to Mars. At that time, the 'Face', located at approximately 40.8o N, 9.6o W, was 275 miles (444 km) from the spacecraft. The 'morning' sun was 25o above the horizon. The picture has a resolution of 14.1 feet (4.3 meters) per pixel, making it ten times higher resolution than the best previous image of the feature, which was taken by the Viking Mission in the mid-1970's. The full image covers an area 2.7 miles (4.4 km) wide and 25.7 miles (41.5 km) long.In this comparison, the best Viking image has been enlarged to 3.3 times its original resolution, and the MOC image has been decreased by a similar 3.3 times, creating images of roughly the same size. In addition, the MOC images have been geometrically transformed to a more overhead projection (different from the mercator map projection of PIA01440 & 1441) for ease of comparison with the Viking image. The left image is a portion of Viking Orbiter 1 frame 070A13, the middle image is a portion of MOC frame shown normally, and the right image is the same MOC frame but with the brightness inverted to simulate the approximate lighting conditions of the Viking image.Processing Image processing has been applied to the images in order to improve the visibility of features. This processing included the following steps: The image was

Fastest Rates for Stochastic Mirror Descent Methods

KAUST Repository

Hanzely, Filip; Richtarik, Peter

2018-01-01

Relative smoothness - a notion introduced by Birnbaum et al. (2011) and rediscovered by Bauschke et al. (2016) and Lu et al. (2016) - generalizes the standard notion of smoothness typically used in the analysis of gradient type methods. In this work we are taking ideas from well studied field of stochastic convex optimization and using them in order to obtain faster algorithms for minimizing relatively smooth functions. We propose and analyze two new algorithms: Relative Randomized Coordinate Descent (relRCD) and Relative Stochastic Gradient Descent (relSGD), both generalizing famous algorithms in the standard smooth setting. The methods we propose can be in fact seen as a particular instances of stochastic mirror descent algorithms. One of them, relRCD corresponds to the first stochastic variant of mirror descent algorithm with linear convergence rate.

Fastest Rates for Stochastic Mirror Descent Methods

KAUST Repository

Hanzely, Filip

2018-03-20

Relative smoothness - a notion introduced by Birnbaum et al. (2011) and rediscovered by Bauschke et al. (2016) and Lu et al. (2016) - generalizes the standard notion of smoothness typically used in the analysis of gradient type methods. In this work we are taking ideas from well studied field of stochastic convex optimization and using them in order to obtain faster algorithms for minimizing relatively smooth functions. We propose and analyze two new algorithms: Relative Randomized Coordinate Descent (relRCD) and Relative Stochastic Gradient Descent (relSGD), both generalizing famous algorithms in the standard smooth setting. The methods we propose can be in fact seen as a particular instances of stochastic mirror descent algorithms. One of them, relRCD corresponds to the first stochastic variant of mirror descent algorithm with linear convergence rate.

Conjugate descent formulation of backpropagation error in ...

African Journals Online (AJOL)

nique of backpropagation was popularized in a paper by Rumelhart, et al. ... the training of a multilayer neural network using a gradient descent approach applied to a .... superior convergence of the conjugate descent method over a standard ...

Hydrological evolution of Atlantis basin, Sirenum Terrae, Mars. Preliminar analysis of MOC and THEMIS images.

Science.gov (United States)

de Pablo, M. A.; Márquez, A.; Centeno, J. D.

The Atlantis basin is one of the martian highlands areas where there was proposed the existence of an ancient lake during the early geological history of Mars [1] [2] [3] [4]. The existence of some morphological features inside the basin and in the surrounding area, allow to check the existence of liquid water in the past of the planet. On the other hand, other morphological features indicate the existence of snow and liquid groundwater in recent times. The detailed study of the geomorphologic features allows to make an approach to the hydrological evolution of the Atlantis basin. The study of the geomorphology of this region has been carried out by means of the analysis of MOC high resolution images obtained by the Mars Global Surveyor mission and the THEMIS images, in the visible spectrum, sent by Mars Odyssey spacecrafts. The most clearly morphological feature indicative of the existence of water in the surface of Mars in the past are the numerous channels that end into Atlantis basin from the highest terrains. In addiction to these fluvial channels, the existence of mass flow deposits is also indicative of the existence of water in the area. Some of these slumps are in the internal slopes of impact craters, but others cover huge extensions around the chaotic terrains of the studied area. The lobated ejecta deposits observed in the Atlantis basin region are indicative of the existence of groundwater (solid or liquid) [5]. Serrated reliefs and tables in the borders of the basins are indicative of the existence of a water sheet. Beneath this water sheet some deposits was formed which was eroded, due to the gradual desiccation of the basin, forming the tables and serrated reliefs. The existence of different chaotic terrains in the area implies the existence of huge amounts of water under the surface according to the different models of chaotic terrain formation [6] [7]. The existence of groundwater could be decided by the existence of collapses in the near to the

Feasibility of a Dragon-Derived Mars Lander for Scientific and Human-Precursor Missions

Science.gov (United States)

Karcz, John S.; Davis, Sanford S.; Allen, Gary A.; Glass, Brian J.; Gonzales, Andrew; Heldmann, Jennifer Lynne; Lemke, Lawrence G.; McKay, Chris; Stoker, Carol R.; Wooster, Paul Douglass;

The Colour and Stereo Surface Imaging System (CaSSIS) for the ExoMars Trace Gas Orbiter

Science.gov (United States)

Thomas, N.; Cremonese, G.; Ziethe, R.; Gerber, M.; Brändli, M.; Bruno, G.; Erismann, M.; Gambicorti, L.; Gerber, T.; Ghose, K.; Gruber, M.; Gubler, P.; Mischler, H.; Jost, J.; Piazza, D.; Pommerol, A.; Rieder, M.; Roloff, V.; Servonet, A.; Trottmann, W.; Uthaicharoenpong, T.; Zimmermann, C.; Vernani, D.; Johnson, M.; Pelò, E.; Weigel, T.; Viertl, J.; De Roux, N.; Lochmatter, P.; Sutter, G.; Casciello, A.; Hausner, T.; Ficai Veltroni, I.; Da Deppo, V.; Orleanski, P.; Nowosielski, W.; Zawistowski, T.; Szalai, S.; Sodor, B.; Tulyakov, S.; Troznai, G.; Banaskiewicz, M.; Bridges, J.C.; Byrne, S.; Debei, S.; El-Maarry, M. R.; Hauber, E.; Hansen, C.J.; Ivanov, A.; Keszthelyil, L.; Kirk, Randolph L.; Kuzmin, R.; Mangold, N.; Marinangeli, L.; Markiewicz, W. J.; Massironi, M.; McEwen, A.S.; Okubo, Chris H.; Tornabene, L.L.; Wajer, P.; Wray, J.J.

2017-01-01

The Colour and Stereo Surface Imaging System (CaSSIS) is the main imaging system onboard the European Space Agency’s ExoMars Trace Gas Orbiter (TGO) which was launched on 14 March 2016. CaSSIS is intended to acquire moderately high resolution (4.6 m/pixel) targeted images of Mars at a rate of 10–20 images per day from a roughly circular orbit 400 km above the surface. Each image can be acquired in up to four colours and stereo capability is foreseen by the use of a novel rotation mechanism. A typical product from one image acquisition will be a 9.5 km×∼45 km">9.5 km×∼45 km9.5 km×∼45 km swath in full colour and stereo in one over-flight of the target thereby reducing atmospheric influences inherent in stereo and colour products from previous high resolution imagers. This paper describes the instrument including several novel technical solutions required to achieve the scientific requirements.

'Endurance' Courtesy of Mars Express

Science.gov (United States)

2004-01-01

NASA's Mars Exploration Rover Opportunity used its panoramic camera to capture this false-color image of the interior of 'Endurance Crater' on the rover's 188th martian day (Aug. 4, 2004). The image data were relayed to Earth by the European Space Agency's Mars Express orbiter. The image was generated from separate frames using the cameras 750-, 530- and 480-nanometer filters.

Deep Space 2: The Mars Microprobe Mission

Science.gov (United States)

Smrekar, Suzanne; Catling, David; Lorenz, Ralph; Magalhães, Julio; Moersch, Jeffrey; Morgan, Paul; Murray, Bruce; Presley-Holloway, Marsha; Yen, Albert; Zent, Aaron; Blaney, Diana

The Mars Microprobe Mission will be the second of the New Millennium Program's technology development missions to planetary bodies. The mission consists of two penetrators that weigh 2.4 kg each and are being carried as a piggyback payload on the Mars Polar Lander cruise ring. The spacecraft arrive at Mars on December 3, 1999. The two identical penetrators will impact the surface at ~190 m/s and penetrate up to 0.6 m. They will land within 1 to 10 km of each other and ~50 km from the Polar Lander on the south polar layered terrain. The primary objective of the mission is to demonstrate technologies that will enable future science missions and, in particular, network science missions. A secondary goal is to acquire science data. A subsurface evolved water experiment and a thermal conductivity experiment will estimate the water content and thermal properties of the regolith. The atmospheric density, pressure, and temperature will be derived using descent deceleration data. Impact accelerometer data will be used to determine the depth of penetration, the hardness of the regolith, and the presence or absence of 10 cm scale layers.

Luteinizing hormone in testicular descent

DEFF Research Database (Denmark)

Toppari, Jorma; Kaleva, Marko M; Virtanen, Helena E

2007-01-01

alone is not sufficient for normal testicular descent. The regulation of androgen production is influenced both by placental human chorionic gonadotropin (hCG) and pituitary luteinizing hormone (LH). There is evidence that the longer pregnancy continues, the more important role pituitary LH may have....... Insulin-like hormone-3 (INSL3) is suggested to be the main regulator of gubernacular development and therefore an apparent regulator of testicular descent. INSL3 production is also related to LH, and reduced INSL3 action is a possible cause for cryptorchidism. Cryptorchid boys have normal testosterone...

Non-homogeneous updates for the iterative coordinate descent algorithm

Science.gov (United States)

Yu, Zhou; Thibault, Jean-Baptiste; Bouman, Charles A.; Sauer, Ken D.; Hsieh, Jiang

2007-02-01

Statistical reconstruction methods show great promise for improving resolution, and reducing noise and artifacts in helical X-ray CT. In fact, statistical reconstruction seems to be particularly valuable in maintaining reconstructed image quality when the dosage is low and the noise is therefore high. However, high computational cost and long reconstruction times remain as a barrier to the use of statistical reconstruction in practical applications. Among the various iterative methods that have been studied for statistical reconstruction, iterative coordinate descent (ICD) has been found to have relatively low overall computational requirements due to its fast convergence. This paper presents a novel method for further speeding the convergence of the ICD algorithm, and therefore reducing the overall reconstruction time for statistical reconstruction. The method, which we call nonhomogeneous iterative coordinate descent (NH-ICD) uses spatially non-homogeneous updates to speed convergence by focusing computation where it is most needed. Experimental results with real data indicate that the method speeds reconstruction by roughly a factor of two for typical 3D multi-slice geometries.

EU-FP7-iMars: Analysis of Mars Multi-Resolution Images using Auto-Coregistration, Data Mining and Crowd Source Techniques: an overview and a request for scientific inputs.

Science.gov (United States)

Muller, Jan-Peter; Gwinner, Klaus; van Gasselt, Stephan; Ivanov, Anton; Morley, Jeremy; Houghton, Robert; Bamford, Steven; Yershov, Vladimir; Sidirpoulos, Panagiotis; Kim, Jungrack

2014-05-01

Understanding the role of different planetary surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 7 years, especially in 3D imaging of surface shape (down to resolutions of 10cm) and subsequent terrain correction of imagery from orbiting spacecraft. This has led to the ability to be able to overlay different epochs back to the mid-1970s, examine time-varying changes (such as the recent discovery of boulder movement [Orloff et al., 2011] or the sublimation of sub-surface ice revealed by meteoritic impact [Byrne et al., 2009] as well as examine geophysical phenomena, such as surface roughness on different length scales. Consequently we are seeing a dramatic improvement in our understanding of surface formation processes. Since January 2004 the ESA Mars Express has been acquiring global data, especially HRSC stereo (12.5-25m nadir images) with 87% coverage with images ≤25m and more than 65% useful for stereo mapping (e.g. atmosphere sufficiently clear). It has been demonstrated [Gwinner et al., 2010] that HRSC has the highest possible planimetric accuracy of ≤25m and is well co-registered with MOLA, which represents the global 3D reference frame. HRSC 3D and terrain-corrected image products therefore represent the best available 3D reference data for Mars. NASA began imaging the surface of Mars, initially from flybys in the 1960s with the first orbiter with images ≤100m in the late 1970s from Viking Orbiter. The most recent orbiter to begin imaging in November 2006 is the NASA MRO which has acquired surface imagery of around 1% of the Martian surface from HiRISE (at ≡20cm) and ≡5% from CTX (≡6m) in stereo. Unfortunately, for most of these NASA images, especially MGS, MO, VO and HiRISE their accuracy of georeferencing is often worse than the quality of Mars reference data from HRSC. This reduces their value for analysing

Space Shuttle 750 psi Helium Regulator Application on Mars Science Laboratory Propulsion

Science.gov (United States)

Mizukami, Masashi; Yankura, George; Rust, Thomas; Anderson, John R.; Dien, Anthony; Garda, Hoshang; Bezer, Mary Ann; Johnson, David; Arndt, Scott

2009-01-01

The Mars Science Laboratory (MSL) is NASA's next major mission to Mars, to be launched in September 2009. It is a nuclear powered rover designed for a long duration mission, with an extensive suite of science instruments. The descent and landing uses a unique 'skycrane' concept, where a rocket-powered descent stage decelerates the vehicle, hovers over the ground, lowers the rover to the ground on a bridle, then flies a safe distance away for disposal. This descent stage uses a regulated hydrazine propulsion system. Performance requirements for the pressure regulator were very demanding, with a wide range of flow rates and tight regulated pressure band. These indicated that a piloted regulator would be needed, which are notoriously complex, and time available for development was short. Coincidentally, it was found that the helium regulator used in the Space Shuttle Orbiter main propulsion system came very close to meeting MSL requirements. However, the type was out of production, and fabricating new units would incur long lead times and technical risk. Therefore, the Space Shuttle program graciously furnished three units for use by MSL. Minor modifications were made, and the units were carefully tuned to MSL requirements. Some of the personnel involved had built and tested the original shuttle units. Delta qualification for MSL application was successfully conducted on one of the units. A pyrovalve slam start and shock test was conducted. Dynamic performance analyses for the new application were conducted, using sophisticated tools developed for Shuttle. Because the MSL regulator is a refurbished Shuttle flight regulator, it will be the only part of MSL which has physically already been in space.

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.

Image Simulation and Assessment of the Colour and Spatial Capabilities of the Colour and Stereo Surface Imaging System (CaSSIS) on the ExoMars Trace Gas Orbiter

Science.gov (United States)

Tornabene, Livio L.; Seelos, Frank P.; Pommerol, Antoine; Thomas, Nicholas; Caudill, C. M.; Becerra, Patricio; Bridges, John C.; Byrne, Shane; Cardinale, Marco; Chojnacki, Matthew; Conway, Susan J.; Cremonese, Gabriele; Dundas, Colin M.; El-Maarry, M. R.; Fernando, Jennifer; Hansen, Candice J.; Hansen, Kayle; Harrison, Tanya N.; Henson, Rachel; Marinangeli, Lucia; McEwen, Alfred S.; Pajola, Maurizio; Sutton, Sarah S.; Wray, James J.

2018-02-01

This study aims to assess the spatial and visible/near-infrared (VNIR) colour/spectral capabilities of the 4-band Colour and Stereo Surface Imaging System (CaSSIS) aboard the ExoMars 2016 Trace Grace Orbiter (TGO). The instrument response functions for the CaSSIS imager was used to resample spectral libraries, modelled spectra and to construct spectrally ( i.e., in I/F space) and spatially consistent simulated CaSSIS image cubes of various key sites of interest and for ongoing scientific investigations on Mars. Coordinated datasets from Mars Reconnaissance Orbiter (MRO) are ideal, and specifically used for simulating CaSSIS. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) provides colour information, while the Context Imager (CTX), and in a few cases the High-Resolution Imaging Science Experiment (HiRISE), provides the complementary spatial information at the resampled CaSSIS unbinned/unsummed pixel resolution (4.6 m/pixel from a 400-km altitude). The methodology used herein employs a Gram-Schmidt spectral sharpening algorithm to combine the ˜18-36 m/pixel CRISM-derived CaSSIS colours with I/F images primarily derived from oversampled CTX images. One hundred and eighty-one simulated CaSSIS 4-colour image cubes (at 18-36 m/pixel) were generated (including one of Phobos) based on CRISM data. From these, thirty-three "fully"-simulated image cubes of thirty unique locations on Mars ( i.e., with 4 colour bands at 4.6 m/pixel) were made. All simulated image cubes were used to test both the colour capabilities of CaSSIS by producing standard colour RGB images, colour band ratio composites (CBRCs) and spectral parameters. Simulated CaSSIS CBRCs demonstrated that CaSSIS will be able to readily isolate signatures related to ferrous (Fe2+) iron- and ferric (Fe3+) iron-bearing deposits on the surface of Mars, ices and atmospheric phenomena. Despite the lower spatial resolution of CaSSIS when compared to HiRISE, the results of this work demonstrate that Ca

Mars Science Laboratory Launch-Arrival Space Study: A Pork Chop Plot Analysis

Science.gov (United States)

Cianciolo, Alicia Dwyer; Powell, Richard; Lockwood, Mary Kae

2006-01-01

Launch-Arrival, or "pork chop", plot analysis can provide mission designers with valuable information and insight into a specific launch and arrival space selected for a mission. The study begins with the array of entry states for each pair of selected Earth launch and Mars arrival dates, and nominal entry, descent and landing trajectories are simulated for each pair. Parameters of interest, such as maximum heat rate, are plotted in launch-arrival space. The plots help to quickly identify launch and arrival regions that are not feasible under current constraints or technology and also provide information as to what technologies may need to be developed to reach a desired region. This paper provides a discussion of the development, application, and results of a pork chop plot analysis to the Mars Science Laboratory mission. This technique is easily applicable to other missions at Mars and other destinations.

Ground Contact Model for Mars Science Laboratory Mission Simulations

Science.gov (United States)

Raiszadeh, Behzad; Way, David

2012-01-01

The Program to Optimize Simulated Trajectories II (POST 2) has been successful in simulating the flight of launch vehicles and entry bodies on earth and other planets. POST 2 has been the primary simulation tool for the Entry Descent, and Landing (EDL) phase of numerous Mars lander missions such as Mars Pathfinder in 1997, the twin Mars Exploration Rovers (MER-A and MER-B) in 2004, Mars Phoenix lander in 2007, and it is now the main trajectory simulation tool for Mars Science Laboratory (MSL) in 2012. In all previous missions, the POST 2 simulation ended before ground impact, and a tool other than POST 2 simulated landing dynamics. It would be ideal for one tool to simulate the entire EDL sequence, thus avoiding errors that could be introduced by handing off position, velocity, or other fight parameters from one simulation to the other. The desire to have one continuous end-to-end simulation was the motivation for developing the ground interaction model in POST 2. Rover landing, including the detection of the postlanding state, is a very critical part of the MSL mission, as the EDL landing sequence continues for a few seconds after landing. The method explained in this paper illustrates how a simple ground force interaction model has been added to POST 2, which allows simulation of the entire EDL from atmospheric entry through touchdown.

Several Guaranteed Descent Conjugate Gradient Methods for Unconstrained Optimization

Directory of Open Access Journals (Sweden)

San-Yang Liu

2014-01-01

Full Text Available This paper investigates a general form of guaranteed descent conjugate gradient methods which satisfies the descent condition gkTdk≤-1-1/4θkgk2  θk>1/4 and which is strongly convergent whenever the weak Wolfe line search is fulfilled. Moreover, we present several specific guaranteed descent conjugate gradient methods and give their numerical results for large-scale unconstrained optimization.

Managing Complexity in the MSL/Curiosity Entry, Descent, and Landing Flight Software and Avionics Verification and Validation Campaign

Science.gov (United States)

Stehura, Aaron; Rozek, Matthew

2013-01-01

The complexity of the Mars Science Laboratory (MSL) mission presented the Entry, Descent, and Landing systems engineering team with many challenges in its Verification and Validation (V&V) campaign. This paper describes some of the logistical hurdles related to managing a complex set of requirements, test venues, test objectives, and analysis products in the implementation of a specific portion of the overall V&V program to test the interaction of flight software with the MSL avionics suite. Application-specific solutions to these problems are presented herein, which can be generalized to other space missions and to similar formidable systems engineering problems.

Mid-Lift-to-Drag Ratio Rigid Vehicle Control System Design and Simulation for Human Mars Entry

Science.gov (United States)

Johnson, Breanna J.; Cerimele, Christopher J.; Stachowiak, Susan J.; Sostaric, Ronald R.; Matz, Daniel A.; Lu, Ping

2018-01-01

The Mid-Lift-to-Drag Ratio Rigid Vehicle (MRV) is a proposed candidate in the NASA Evolvable Mars Campaign's (EMC) Pathfinder Entry, Descent, and Landing (EDL) architecture study. The purpose of the study is to design a mission and vehicle capable of transporting a 20mt payload to the surface of Mars. The MRV is unique in its rigid, asymmetrical lifting-body shape which enables a higher lift-to-drag ratio (L/D) than the typical robotic Mars entry capsule vehicles that carry much less mass. This paper presents the formulation and six-degree-of-freedom (6DOF) performance of the MRV's control system, which uses both aerosurfaces and a propulsive reaction control system (RCS) to affect longitudinal and lateral directional behavior.

Overview of the Mars Sample Return Earth Entry Vehicle

Science.gov (United States)

Dillman, Robert; Corliss, James

2008-01-01

NASA's Mars Sample Return (MSR) project will bring Mars surface and atmosphere samples back to Earth for detailed examination. Langley Research Center's MSR Earth Entry Vehicle (EEV) is a core part of the mission, protecting the sample container during atmospheric entry, descent, and landing. Planetary protection requirements demand a higher reliability from the EEV than for any previous planetary entry vehicle. An overview of the EEV design and preliminary analysis is presented, with a follow-on discussion of recommended future design trade studies to be performed over the next several years in support of an MSR launch in 2018 or 2020. Planned topics include vehicle size for impact protection of a range of sample container sizes, outer mold line changes to achieve surface sterilization during re-entry, micrometeoroid protection, aerodynamic stability, thermal protection, and structural materials selection.

Red Dragon: Low-cost Access to the Surface of Mars using Commercial Capabilities

Science.gov (United States)

Karcz, John; Davis, S. M.; Aftosmis, M. J.; Allen, G. A.; Bakhtian, N. M.; Dyakonov, A. A.; Edquist, K. T.; Glass, B. J.; Gonzales, A. A.; Heldmann, J. L.;

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.

Effects of the Phoenix Lander descent thruster plume on the Martian surface

Science.gov (United States)

Plemmons, D. H.; Mehta, M.; Clark, B. C.; Kounaves, S. P.; Peach, L. L.; Renno, N. O.; Tamppari, L.; Young, S. M. M.

2008-08-01

The exhaust plume of Phoenix's hydrazine monopropellant pulsed descent thrusters will impact the surface of Mars during its descent and landing phase in the northern polar region. Experimental and computational studies have been performed to characterize the chemical compounds in the thruster exhausts. No undecomposed hydrazine is observed above the instrument detection limit of 0.2%. Forty-five percent ammonia is measured in the exhaust at steady state. Water vapor is observed at a level of 0.25%, consistent with fuel purity analysis results. Moreover, the dynamic interactions of the thruster plumes with the ground have been studied. Large pressure overshoots are produced at the ground during the ramp-up and ramp-down phases of the duty cycle of Phoenix's pulsed engines. These pressure overshoots are superimposed on the 10 Hz quasi-steady ground pressure perturbations with amplitude of about 5 kPa (at touchdown altitude) and have a maximum amplitude of about 20-40 kPa. A theoretical explanation for the physics that causes these pressure perturbations is briefly described in this article. The potential for soil erosion and uplifting at the landing site is also discussed. The objectives of the research described in this article are to provide empirical and theoretical data for the Phoenix Science Team to mitigate any potential problem. The data will also be used to ensure proper interpretation of the results from on-board scientific instrumentation when Martian soil samples are analyzed.

Mars Pathfinder

Science.gov (United States)

Murdin, P.

2000-11-01

First of NASA's Discovery missions. Launched in December 1996 and arrived at Mars on 4 July 1997. Mainly intended as a technology demonstration mission. Used airbags to cushion the landing on Mars. The Carl Sagan Memorial station returned images of an ancient flood plain in Ares Vallis. The 10 kg Sojourner rover used an x-ray spectrometer to study the composition of rocks and travelled about 100 ...

Gender difference in metacarpal descent of fifth metacarpal

International Nuclear Information System (INIS)

Rafique, A.; Ali, H.; Ghani, S.

2006-01-01

To determine the difference in metacarpal descent of fifth metacarpal between men and women. Skyline of the 2nd and 3rd metacarpals were used as reference line, from which the descent of the 5th metacarpal head was measured. The position of 5th metacarpal head was documented as angle X. Metacarpal descent was defined as the difference between angle 'X' in relaxed and clenched fist position. The relaxed position was standardized by placing the forearm, wrist and palm on a shaped woodblock such that the wrist would be held in 25 - 30 degree in extension by a triangular spur, supported the 3rd metacarpal only. It was ensured that the movement of 4th and 5th metacarpals were not impaired. Analysis of variance was performed to compare the significance of means between genders at p < 0.05 level of significance. Metacarpal descent of the 5th metacarpal of both hands was significantly greater for women, with a mean of 7 degree as compared with a mean of 4 degree for the men. This decrease in angle 'X' was significant for the right 5th metacarpal relaxed and fist position and the fist position on the left. In contrast, women showed no significant differences between the various age groups for any of the variables tested.There was no relationship between metacarpal descent and hand dominance.Difference in metacarpal descent between men and women is significant and must be kept in mind when hand function is evaluated in both genders to assess the outcome of treatment and rehabilitation. (author)

Image simulation and assessment of the colour and spatial capabilities of the Colour and Stereo Surface Imaging System (CaSSIS) on the ExoMars Trace Gas Orbiter

Science.gov (United States)

Tornabene, Livio L.; Seelos, Frank P.; Pommerol, Antoine; Thomas, Nicolas; Caudill, Christy M.; Becerra, Patricio; Bridges, John C.; Byrne, Shane; Cardinale, Marco; Chojnacki, Matthew; Conway, Susan J.; Cremonese, Gabriele; Dundas, Colin M.; El-Maarry, M. R.; Fernando, Jennifer; Hansen, Candice J.; Hansen, Kayle; Harrison, Tanya N.; Henson, Rachel; Marinangeli, Lucia; McEwen, Alfred S.; Pajola, Maurizio; Sutton, Sarah S.; Wray, James J.

2018-01-01

This study aims to assess the spatial and visible/near-infrared (VNIR) colour/spectral capabilities of the 4-band Colour and Stereo Surface Imaging System (CaSSIS) aboard the ExoMars 2016 Trace Grace Orbiter (TGO). The instrument response functions for the CaSSIS imager was used to resample spectral libraries, modelled spectra and to construct spectrally (i.e., in I/F space) and spatially consistent simulated CaSSIS image cubes of various key sites of interest and for ongoing scientific investigations on Mars. Coordinated datasets from Mars Reconnaissance Orbiter (MRO) are ideal, and specifically used for simulating CaSSIS. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) provides colour information, while the Context Imager (CTX), and in a few cases the High-Resolution Imaging Science Experiment (HiRISE), provides the complementary spatial information at the resampled CaSSIS unbinned/unsummed pixel resolution (4.6 m/pixel from a 400-km altitude). The methodology used herein employs a Gram-Schmidt spectral sharpening algorithm to combine the ∼18–36 m/pixel CRISM-derived CaSSIS colours with I/F images primarily derived from oversampled CTX images. One hundred and eighty-one simulated CaSSIS 4-colour image cubes (at 18–36 m/pixel) were generated (including one of Phobos) based on CRISM data. From these, thirty-three “fully”-simulated image cubes of thirty unique locations on Mars (i.e., with 4 colour bands at 4.6 m/pixel) were made. All simulated image cubes were used to test both the colour capabilities of CaSSIS by producing standard colour RGB images, colour band ratio composites (CBRCs) and spectral parameters. Simulated CaSSIS CBRCs demonstrated that CaSSIS will be able to readily isolate signatures related to ferrous (Fe2+) iron- and ferric (Fe3+) iron-bearing deposits on the surface of Mars, ices and atmospheric phenomena. Despite the lower spatial resolution of CaSSIS when compared to HiRISE, the results of this work demonstrate that

Radio Telescopes to Keep Sharp Eye on Mars Lander

Science.gov (United States)

2008-05-01

As NASA's Phoenix Mars Lander descends through the Red Planet's atmosphere toward its landing on May 25, its progress will be scrutinized by radio telescopes from the National Radio Astronomy Observatory (NRAO). At NRAO control rooms in Green Bank, West Virginia, and Socorro, New Mexico, scientists, engineers and technicians will be tracking the faint signal from the lander, 171 million miles from Earth. The GBT Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF To make a safe landing, Phoenix must make a risky descent, slowing down from nearly 13,000 mph at the top of the Martian atmosphere to only 5 mph in the final seconds before touchdown. NASA officials point out that fewer than half of all Mars landing missions have been successful, but the scientific rewards of success are worth the risk. Major events in the spacecraft's atmospheric entry, descent and landing will be marked by changes in the Doppler Shift in the frequency of the vehicle's radio signal. Doppler Shift is the change in frequency caused by relative motion between the transmitter and receiver. At Green Bank, NRAO and NASA personnel will use the giant Robert C. Byrd Green Bank Telescope (GBT) to follow the Doppler changes and verify that the descent is going as planned. The radio signal from Phoenix is designed to be received by other spacecraft in Mars orbit, then relayed to Earth. However, the GBT, a dish antenna with more than two acres of collecting surface and highly-sensitive receivers, can directly receive the transmissions from Phoenix. "We'll see the frequency change as Phoenix slows down in the Martian atmosphere, then there will be a big change when the parachute deploys," said NRAO astronomer Frank Ghigo. When the spacecraft's rocket thrusters slow it down for its final, gentle touchdown, its radio frequency will stabilize, Ghigo said. "We'll have confirmation of these major events through our direct reception several seconds earlier than the controllers at NASA's Jet Propulsion

Integrated Targeting and Guidance for Powered Planetary Descent

Science.gov (United States)

Azimov, Dilmurat M.; Bishop, Robert H.

2018-02-01

This paper presents an on-board guidance and targeting design that enables explicit state and thrust vector control and on-board targeting for planetary descent and landing. These capabilities are developed utilizing a new closed-form solution for the constant thrust arc of the braking phase of the powered descent trajectory. The key elements of proven targeting and guidance architectures, including braking and approach phase quartics, are employed. It is demonstrated that implementation of the proposed solution avoids numerical simulation iterations, thereby facilitating on-board execution of targeting procedures during the descent. It is shown that the shape of the braking phase constant thrust arc is highly dependent on initial mass and propulsion system parameters. The analytic solution process is explicit in terms of targeting and guidance parameters, while remaining generic with respect to planetary body and descent trajectory design. These features increase the feasibility of extending the proposed integrated targeting and guidance design to future cargo and robotic landing missions.

EU-FP7-iMARS: analysis of Mars multi-resolution images using auto-coregistration, data mining and crowd source techniques: A Final Report on the very variable surface of Mars

Science.gov (United States)

Muller, Jan-Peter; Sidiropoulos, Panagiotis; Tao, Yu; Putri, Kiky; Campbell, Jacqueline; Xiong, Si-Ting; Gwinner, Klaus; Willner, Konrad; Fanara, Lida; Waehlisch, Marita; Walter, Sebastian; Schreiner, Bjoern; Steikert, Ralf; Ivanov, Anton; Cantini, Federico; Wardlaw, Jessica; Sprinks, James; Houghton, Robert; Kim, Jung-Rack

2017-04-01

There has been a revolution in 3D surface imaging of Mars over the last 12 years with systematic stereoscopy from HRSC. Digital Terrain Models (DTMs) and OrthoRectified Images (ORIs) have been produced for almost 50% of the Martian surface. DLR, together with the HRSC science team, produced 3D HRSC mosaic products for large regions comprising around 100 individual strips per region (MC-11E/W). UCL processed full coverage of DTMs over the South Polar Residual Cap (SPRC) and started work on the North Polar Layered Deposits (NPLD). The iMars project has been exploiting this unique set of 3D products as a basemap to co-register NASA imagery going back to the 1970s. UCL have developed an automated processing chain for CTX and HiRISE 3D processing to densify the global HRSC dataset with DTMs down to 18m and 75cm respectively using a modification of the open source NASA Ames Stereo Pipeline [1]. 1542 CTX DTMs + ORIs were processed using the Microsoft Azure® cloud and an in-house linux cluster. It is planned to process around 10% of the total HiRISE stereo-DTMs before the end of the project. A fully Automated Co-Registration and Orthorectification (ACRO) system has been developed at UCL and applied to the production of around some 15,000 NASA images. These were co-registered co-registered to a HRSC pixel (typically 12.5m/pixel) and orthorectified to HRSC DTMs of 50-150m spacing [2] over MC-11E/W. All of these new products images are viewable through an OGC-compliant webGIS developed at FUB,. This includes tools for viewing temporal sequences of co-registered ORIs over the same area [3]. Corresponding MARSIS and SHARAD data can be viewed through a QGIS plugin made publicly available [4]. An automated data mining system has been developed at UCL [5] for change detection to search and classify features in images going back to Viking Orbiter of IFoV ≤100m. In parallel, a citizen science project at Nottingham University [6] has defined training samples for classification of

Detection of Crater Rims by Image Analysis in Very High Resolution Images of Mars, Mercury and the Moon

Science.gov (United States)

Pina, P.; Marques, J. S.; Bandeira, L.

2013-12-01

The adaptive nature of automated crater detection algorithms permits achieving a high level of autonomous detections in different surfaces and consequently becoming an important tool in the update of crater catalogues. Nevertheless, the available approaches assume all craters as circular and only provide as output the radius and location of each crater. However, the delineation of impact craters following the local variability of the rims is also important to, among others, evaluate their degree of degradation or preservation, namely those studies related to ancient climate analysis. This contour determination is normally prepared in a manual way but can advantageously be done by image analysis methods, eliminating subjectivity and allowing large scale delineations. We have recently proposed a pair of independent approaches to tackle with this problem, one based on processing the crater image in polar coordinates [1], the other using morphological operators [2], which achieved a good degree of success on very high resolution images from Mars [3-4], but where enough room for improvement was still available. Thus, the integration of both approaches into a single one, suppressing the individual drawbacks of the previous approaches, permitted to strength the detection procedure. We describe now the novel sequence of processing that we have built and test it intensively in a wider variety of planetary surfaces, namely, those of Mars, Mercury and the Moon, using the very high resolution images provided by HiRISE, MDIS and LROC cameras. The automated delineations of the craters are compared to a ground-truth reference (manually delineated contours), so a quantitative evaluation can be performed; on a dataset constituted by more than one thousand impact craters we have obtained a global high delineation rate. The breakdown by crater size on each surface is performed. The whole processing procedure works on raster images and also delivers the output in the same image format

Noise annoyance caused by continuous descent approaches compared to regular descent procedures

NARCIS (Netherlands)

White, K.; Arntzen, M.; Walker, F.; Waiyaki, F.M.; Meeter, M.; Bronkhorst, A.W.

2017-01-01

During Continuous Descent Approaches (CDAs) aircraft glide towards the runway resulting in reduced noise and fuel usage. Here, we investigated whether such landings cause less noise annoyance than a regular stepwise approach. Both landing types were compared in a controlled laboratory setting with a

Two Moons and the Pleiades from Mars

Science.gov (United States)

2005-01-01

[figure removed for brevity, see original site] Inverted image of two moons and the Pleiades from Mars Taking advantage of extra solar energy collected during the day, NASA's Mars Exploration Rover Spirit recently settled in for an evening of stargazing, photographing the two moons of Mars as they crossed the night sky. In this view, the Pleiades, a star cluster also known as the 'Seven Sisters,' is visible in the lower left corner. The bright star Aldebaran and some of the stars in the constellation Taurus are visible on the right. Spirit acquired this image the evening of martian day, or sol, 590 (Aug. 30, 2005). The image on the right provides an enhanced-contrast view with annotation. Within the enhanced halo of light is an insert of an unsaturated view of Phobos taken a few images later in the same sequence. On Mars, Phobos would be easily visible to the naked eye at night, but would be only about one-third as large as the full Moon appears from Earth. Astronauts staring at Phobos from the surface of Mars would notice its oblong, potato-like shape and that it moves quickly against the background stars. Phobos takes only 7 hours, 39 minutes to complete one orbit of Mars. That is so fast, relative to the 24-hour-and-39-minute sol on Mars (the length of time it takes for Mars to complete one rotation), that Phobos rises in the west and sets in the east. Earth's moon, by comparison, rises in the east and sets in the west. The smaller martian moon, Deimos, takes 30 hours, 12 minutes to complete one orbit of Mars. That orbital period is longer than a martian sol, and so Deimos rises, like most solar system moons, in the east and sets in the west. Scientists will use images of the two moons to better map their orbital positions, learn more about their composition, and monitor the presence of nighttime clouds or haze. Spirit took the five images that make up this composite with the panoramic camera, using the camera's broadband filter, which was designed specifically

Automation for Accommodating Fuel-Efficient Descents in Constrained Airspace

Science.gov (United States)

Coopenbarger, Richard A.

2010-01-01

Continuous descents at low engine power are desired to reduce fuel consumption, emissions and noise during arrival operations. The challenge is to allow airplanes to fly these types of efficient descents without interruption during busy traffic conditions. During busy conditions today, airplanes are commonly forced to fly inefficient, step-down descents as airtraffic controllers work to ensure separation and maximize throughput. NASA in collaboration with government and industry partners is developing new automation to help controllers accommodate continuous descents in the presence of complex traffic and airspace constraints. This automation relies on accurate trajectory predictions to compute strategic maneuver advisories. The talk will describe the concept behind this new automation and provide an overview of the simulations and flight testing used to develop and refine its underlying technology.

A Multidisciplinary Tool for Systems Analysis of Planetary Entry, Descent, and Landing (SAPE)

Science.gov (United States)

Samareh, Jamshid A.

2009-01-01

SAPE is a Python-based multidisciplinary analysis tool for systems analysis of planetary entry, descent, and landing (EDL) for Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Titan. The purpose of SAPE is to provide a variable-fidelity capability for conceptual and preliminary analysis within the same framework. SAPE includes the following analysis modules: geometry, trajectory, aerodynamics, aerothermal, thermal protection system, and structural sizing. SAPE uses the Python language-a platform-independent open-source software for integration and for the user interface. The development has relied heavily on the object-oriented programming capabilities that are available in Python. Modules are provided to interface with commercial and government off-the-shelf software components (e.g., thermal protection systems and finite-element analysis). SAPE runs on Microsoft Windows and Apple Mac OS X and has been partially tested on Linux.

Mars Ascent Vehicle-Propellant Aging

Science.gov (United States)

Dankanich, John; Rousseau, Jeremy; Williams, Jacob

2015-01-01

This project is to develop and test a new propellant formulation specifically for the Mars Ascent Vehicle (MAV) for the robotic Mars Sample Return mission. The project was initiated under the Planetary Sciences Division In-Space Propulsion Technology (ISPT) program and is continuing under the Mars Exploration Program. The two-stage, solid motor-based MAV has been the leading MAV solution for more than a decade. Additional studies show promise for alternative technologies including hybrid and bipropellant options, but the solid motor design has significant propellant density advantages well suited for physical constraints imposed while using the SkyCrane descent stage. The solid motor concept has lower specific impulse (Isp) than alternatives, but if the first stage and payload remain sufficiently small, the two-stage solid MAV represents a potential low risk approach to meet the mission needs. As the need date for the MAV slips, opportunities exist to advance technology with high on-ramp potential. The baseline propellant for the MAV is currently the carboxyl terminated polybutadiene (CTPB) based formulation TP-H-3062 due to its advantageous low temperature mechanical properties and flight heritage. However, the flight heritage is limited and outside the environments, the MAV must endure. The ISPT program competed a propellant formulation project with industry and selected ATK to develop a new propellant formulation specifically for the MAV application. Working with ATK, a large number of propellant formulations were assessed to either increase performance of a CTPB propellant or improve the low temperature mechanical properties of a hydroxyl terminated polybutadiene (HTPB) propellant. Both propellants demonstrated potential to increase performance over heritage options, but an HTPB propellant formulation, TP-H-3544, was selected for production and testing. The test plan includes propellant aging first at high vacuum conditions, representative of the Mars transit

Design of automation tools for management of descent traffic

Science.gov (United States)

Erzberger, Heinz; Nedell, William

1988-01-01

The design of an automated air traffic control system based on a hierarchy of advisory tools for controllers is described. Compatibility of the tools with the human controller, a key objective of the design, is achieved by a judicious selection of tasks to be automated and careful attention to the design of the controller system interface. The design comprises three interconnected subsystems referred to as the Traffic Management Advisor, the Descent Advisor, and the Final Approach Spacing Tool. Each of these subsystems provides a collection of tools for specific controller positions and tasks. This paper focuses primarily on the Descent Advisor which provides automation tools for managing descent traffic. The algorithms, automation modes, and graphical interfaces incorporated in the design are described. Information generated by the Descent Advisor tools is integrated into a plan view traffic display consisting of a high-resolution color monitor. Estimated arrival times of aircraft are presented graphically on a time line, which is also used interactively in combination with a mouse input device to select and schedule arrival times. Other graphical markers indicate the location of the fuel-optimum top-of-descent point and the predicted separation distances of aircraft at a designated time-control point. Computer generated advisories provide speed and descent clearances which the controller can issue to aircraft to help them arrive at the feeder gate at the scheduled times or with specified separation distances. Two types of horizontal guidance modes, selectable by the controller, provide markers for managing the horizontal flightpaths of aircraft under various conditions. The entire system consisting of descent advisor algorithm, a library of aircraft performance models, national airspace system data bases, and interactive display software has been implemented on a workstation made by Sun Microsystems, Inc. It is planned to use this configuration in operational

Mars MetNet Mission Status

Science.gov (United States)

Harri, Ari-Matti; Aleksashkin, Sergei; Arruego, Ignacio; Schmidt, Walter; Genzer, Maria; Vazquez, Luis; Haukka, Harri

2015-04-01

New kind of planetary exploration mission for Mars is under development in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semi-hard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor [1] mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide significant insights in to the Martian atmospheric behavior. The key technologies of the MetNet Lander have been qualified and the electrical qualification model (EQM) of the payload bay has been built and successfully tested. 1. MetNet Lander The MetNet landing vehicles are using an inflatable entry and descent system instead of rigid heat shields and parachutes as earlier semi-hard landing devices have used. This way the ratio of the payload mass to the overall mass is optimized. The landing impact will burrow the payload container into the Martian soil providing a more favorable thermal environment for the electronics and a suitable orientation of the telescopic boom with external sensors and the radio link antenna. It is planned to deploy several tens of MNLs on the Martian surface operating at least partly at the same time to allow meteorological network science. 2. Scientific Payload The payload of the two MNL precursor models includes the following instruments: Atmospheric instruments: 1. MetBaro Pressure device 2. MetHumi Humidity device 3. MetTemp Temperature sensors Optical devices: 1. PanCam Panoramic 2. MetSIS Solar irradiance sensor with OWLS optical wireless system for data transfer 3. DS Dust sensor The descent processes dynamic properties are monitored by a special 3-axis accelerometer combined with a 3-axis gyrometer. The data will be sent via auxiliary beacon antenna throughout the

Final descent for CMS

CERN Multimedia

The 15th and last section of the CMS detector was lowered on Tuesday 22 January. The YE-1 endcap (1430 tonnes) began its 100-metre descent at 7 am and arrived gently on the floor of the experiment hall at 5.30 pm.

Exomars orbiter science and data-relay mission / looking for trace gases on Mars

Science.gov (United States)

Fratacci, Olivier

EXOMARS Orbiter Module: looking for trace gas on Mars and providing data relay support for future Mars Surface assets O.Fratacci, M.Mesrine, H.Renault, Thales Alenia Space France B.Musetti, M.Montagna, Thales Alenia Space Italy M.Kesselmann, M.Barczewski OHB P.Mitschdoerfer, D.Dellantonio Euro-pean Space Agency / ESTEC The European Space Agency (ESA) in a joint cooperation with NASA, will launch in 2016 the EXOMARS spacecraft composite to develop European landing technologies and provide a science orbiter with data-relay capability around Mars until end 2022. The spacecraft composite is composed of the Orbitr Module (OM), provided by TAS-France, an entry descent and landing demonstrator module (EDM) provided by TAS-Italy, and a set of six scientific payloads to be selected by the JPL during 2010. Recent observations of the planet Mars have indicated detection of methane as well as temporal, perhaps spatial variability in the detected signal while current photochemical models cannot explain the presence of methane in the atmosphere of Mars nor its reported rapid variations in space and time. The triple scientific objectives that drive the selection of these six instruments for the Exomars 2016 mission is to detect trace gases in Mars atmosphere, to characterise their spatial and temporal variation and to explore the source of the key trace gases (e.g. methane) on the surface. The launch is scheduled in January 2016 from Kennedy Space Center (KSC) using an ATLAS V 421 launcher with a total launch mass of 4.4 tons. After release of the EDM on Mars, the OM will perform the Mars Orbit Insertion manoeuvre and then reduce its elliptic orbit by implementing the first European Aerobraking around Mars for about 6 to 9 months, to finally end on a circular 400x400km orbit with an altitude in the range of 350km to 420km. From this orbit, a science phase will follow lasting 2 years in which the Mars atmosphere and surface is continuously observed. Science instruments composed of

43 CFR 10.14 - Lineal descent and cultural affiliation.

Science.gov (United States)

2010-10-01

... Hawaiian organization and the human remains, funerary objects, sacred objects, or objects of cultural... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Lineal descent and cultural affiliation... GRAVES PROTECTION AND REPATRIATION REGULATIONS General § 10.14 Lineal descent and cultural affiliation...

LA GRANDE DESCENTE

CERN Multimedia

The first endcap disc of CMS being lowered slowly and carefully 100 m underground into the experimental cavern. The disc is one of 15 large pieces to make the grand descent.  The uniquely shaped slice, 16 m high, about 50 cm thick weighs 400 tonnes. The two HF that were lowered earlier in November can also be seen in the foreground and background.  

Development and descent of the testis in relation to cryptorchidism

DEFF Research Database (Denmark)

Virtanen, Helena E; Cortes, Dina; Rajpert-De Meyts, Ewa

2007-01-01

The testis descends in two phases. Animal studies suggest, that the transabdominal descent of the testis depends on the insulin-like hormone 3 (INSL3). Androgens are important in the inguinoscrotal testicular descent in animals and humans. In general, the cause of cryptorchidism is unknown...... and the aetiology is possibly multifactorial. Histological changes in cryptorchid testes demonstrate disturbed development. Conclusion: Since testicular descent is regulated by testis-derived hormones, cryptorchidism may reflect a functional defect of the testis....

Preparing for Mars: The Evolvable Mars Campaign 'Proving Ground' Approach

Science.gov (United States)

Bobskill, Marianne R.; Lupisella, Mark L.; Mueller, Rob P.; Sibille, Laurent; Vangen, Scott; Williams-Byrd, Julie

2015-01-01

provide the foundation required to enable a variety of possible destinations and missions consistent with the Evolvable Mars Campaign.. The International Space Station will be used to the greatest extent possible for exploration capability and technology development. Beyond this, NASA is evaluating a number of options for Proving Ground missions. An "Asteroid Redirect Mission" will demonstrate needed capabilities (e.g., Solar Electric Propulsion) and transportation systems for the crew (i.e., Space Launch System and Orion) and for cargo (i.e., Asteroid Redirect Vehicle). The Mars 2020 mission and follow-on robotic precursor missions will gather Mars surface environment information and will mature technologies. NASA is considering emplacing a small pressurized module in cis-lunar space to support crewed operations of increasing duration and to serve as a platform for critical exploration capabilities testing (e.g., radiation mitigation; extended duration deep space habitation). In addition, "opportunistic mission operations" could demonstrate capabilities not on the Mars critical path that may, nonetheless, enhance exploration operations (e.g., teleoperations, crew assisted Mars sample return). The Proving Ground may also include "pathfinder" missions to test and demonstrate specific capabilities at Mars (e.g., entry, descent, and landing). This paper describes the (1) process used to conduct an architecture-driven technology development assessment, (2) exploration mission critical and supporting capabilities, and (3) approach for addressing test and demonstration opportunities encompassing the spectrum of flight elements and destinations consistent with the Evolvable Mars Campaign.

MODIFIED ARMIJO RULE ON GRADIENT DESCENT AND CONJUGATE GRADIENT

Directory of Open Access Journals (Sweden)

ZURAIDAH FITRIAH

2017-10-01

Full Text Available Armijo rule is an inexact line search method to determine step size in some descent method to solve unconstrained local optimization. Modified Armijo was introduced to increase the numerical performance of several descent algorithms that applying this method. The basic difference of Armijo and its modified are in existence of a parameter and estimating the parameter that is updated in every iteration. This article is comparing numerical solution and time of computation of gradient descent and conjugate gradient hybrid Gilbert-Nocedal (CGHGN that applying modified Armijo rule. From program implementation in Matlab 6, it's known that gradient descent was applying modified Armijo more effectively than CGHGN from one side: iteration needed to reach some norm of the gradient  (input by the user. The amount of iteration was representing how long the step size of each algorithm in each iteration. In another side, time of computation has the same conclusion.

Creating an Immersive Mars Experience Using Unity3D

Science.gov (United States)

Miles, Sarah

2011-01-01

Between the two Mars Exploration Rovers, Spirit and Opportunity, NASA has collected over 280,000 images while studying the Martian surface. This number will continue to grow, with Opportunity continuing to send images and with another rover, Curiosity, launching soon. Using data collected by and for these Mars rovers, I am contributing to the creation of virtual experiences that will expose the general public to Mars. These experiences not only work to increase public knowledge, but they attempt to do so in an engaging manner more conducive to knowledge retention by letting others view Mars through the rovers' eyes. My contributions include supporting image viewing (for example, allowing users to click on panoramic images of the Martian surface to access closer range photos) as well as enabling tagging of points of interest. By creating a more interactive way of viewing the information we have about Mars, we are not just educating the public about a neighboring planet. We are showing the importance of doing such research.

Studies of the hormonal control of postnatal testicular descent in the rat.

Science.gov (United States)

Spencer, J R; Vaughan, E D; Imperato-McGinley, J

1993-03-01

Dihydrotestosterone is believed to control the transinguinal phase of testicular descent based on hormonal manipulation studies performed in postnatal rats. In the present study, these hormonal manipulation experiments were repeated, and the results were compared with those obtained using the antiandrogens flutamide and cyproterone acetate. 17 beta-estradiol completely blocked testicular descent, but testosterone and dihydrotestosterone were equally effective in reversing this inhibition. Neither flutamide nor cyproterone acetate prevented testicular descent in postnatal rats despite marked peripheral antiandrogenic action. Further analysis of the data revealed a correlation between testicular size and descent. Androgen receptor blockade did not produce a marked reduction in testicular size and consequently did not prevent testicular descent, whereas estradiol alone caused marked testicular atrophy and testicular maldescent. Reduction of the estradiol dosage or concomitant administration of androgens or human chorionic gonadotropin resulted in both increased testicular size and degree of descent. These data suggest that growth of the neonatal rat testis may contribute to its passage into the scrotum.

Image Quality Assessment of JPEG Compressed Mars Science Laboratory Mastcam Images using Convolutional Neural Networks

Science.gov (United States)

Kerner, H. R.; Bell, J. F., III; Ben Amor, H.

2017-12-01

The Mastcam color imaging system on the Mars Science Laboratory Curiosity rover acquires images within Gale crater for a variety of geologic and atmospheric studies. Images are often JPEG compressed before being downlinked to Earth. While critical for transmitting images on a low-bandwidth connection, this compression can result in image artifacts most noticeable as anomalous brightness or color changes within or near JPEG compression block boundaries. In images with significant high-frequency detail (e.g., in regions showing fine layering or lamination in sedimentary rocks), the image might need to be re-transmitted losslessly to enable accurate scientific interpretation of the data. The process of identifying which images have been adversely affected by compression artifacts is performed manually by the Mastcam science team, costing significant expert human time. To streamline the tedious process of identifying which images might need to be re-transmitted, we present an input-efficient neural network solution for predicting the perceived quality of a compressed Mastcam image. Most neural network solutions require large amounts of hand-labeled training data for the model to learn the target mapping between input (e.g. distorted images) and output (e.g. quality assessment). We propose an automatic labeling method using joint entropy between a compressed and uncompressed image to avoid the need for domain experts to label thousands of training examples by hand. We use automatically labeled data to train a convolutional neural network to estimate the probability that a Mastcam user would find the quality of a given compressed image acceptable for science analysis. We tested our model on a variety of Mastcam images and found that the proposed method correlates well with image quality perception by science team members. When assisted by our proposed method, we estimate that a Mastcam investigator could reduce the time spent reviewing images by a minimum of 70%.

Mars Hand Lens Imager (MAHLI) Efforts and Observations at the Rocknest Eolian Sand Shadow in Curiosity's Gale Crater Field Site

Science.gov (United States)

Edgett, K. S.; Yingst, R. A.; Minitti, M. E.; Goetz, W.; Kah, L. C.; Kennedy, M. R.; Lipkaman, L. J.; Jensen, E. H.; Anderson, R. C.; Beegle, L. W.;

Mars for Earthlings: an analog approach to Mars in undergraduate education.

Science.gov (United States)

Chan, Marjorie; Kahmann-Robinson, Julia

2014-01-01

Mars for Earthlings (MFE) is a terrestrial Earth analog pedagogical approach to teaching undergraduate geology, planetary science, and astrobiology. MFE utilizes Earth analogs to teach Mars planetary concepts, with a foundational backbone in Earth science principles. The field of planetary science is rapidly changing with new technologies and higher-resolution data sets. Thus, it is increasingly important to understand geological concepts and processes for interpreting Mars data. MFE curriculum is topically driven to facilitate easy integration of content into new or existing courses. The Earth-Mars systems approach explores planetary origins, Mars missions, rocks and minerals, active driving forces/tectonics, surface sculpting processes, astrobiology, future explorations, and hot topics in an inquiry-driven environment. Curriculum leverages heavily upon multimedia resources, software programs such as Google Mars and JMARS, as well as NASA mission data such as THEMIS, HiRISE, CRISM, and rover images. Two years of MFE class evaluation data suggest that science literacy and general interest in Mars geology and astrobiology topics increased after participation in the MFE curriculum. Students also used newly developed skills to create a Mars mission team presentation. The MFE curriculum, learning modules, and resources are available online at http://serc.carleton.edu/marsforearthlings/index.html.

MASS MOVEMENTS' DETECTION IN HIRISE IMAGES OF THE NORTH POLE OF MARS

Directory of Open Access Journals (Sweden)

L. Fanara

2016-06-01

Full Text Available We are investigating change detection techniques to automatically detect mass movements at the steep north polar scarps of Mars, in order to improve our understanding of these dynamic processes. Here we focus on movements of blocks specifically. The precise detection of such small changes requires an accurate co-registration of the images, which is achieved by ortho-rectifying them using High Resolution Imaging Science Experiment (HiRISE Digital Terrain Models (DTMs. Moreover, we deal with the challenge of deriving the true shape of the moved blocks. In a next step, these results are combined with findings based on HiRISE DTMs from different points in time in order to estimate the volume of mass movements.

Hydrovolcanic features on Mars: Preliminary observations from the first Mars year of HiRISE imaging

Science.gov (United States)

Keszthelyi, L.P.; Jaeger, W.L.; Dundas, C.M.; Martinez-Alonso, S.; McEwen, A.S.; Milazzo, M.P.

2010-01-01

We provide an overview of features indicative of the interaction between water and lava and/or magma on Mars as seen by the High Resolution Imaging Science Experiment (HiRISE) camera during the Primary Science Phase of the Mars Reconnaissance Orbiter (MRO) mission. The ability to confidently resolve meter-scale features from orbit has been extremely useful in the study of the most pristine examples. In particular, HiRISE has allowed the documentation of previously undescribed features associated with phreatovolcanic cones (formed by the interaction of lava and groundwater) on rapidly emplaced flood lavas. These include "moats" and "wakes" that indicate that the lava crust was thin and mobile, respectively [Jaeger, W.L., Keszthelyi, L.P., McEwen, A.S., Dundas, C.M., Russel, P.S., 2007. Science 317, 1709-1711]. HiRISE has also discovered entablature-style jointing in lavas that is indicative of water-cooling [Milazzo, M.P., Keszthelyi, L.P., Jaeger, W.L., Rosiek, M., Mattson, S., Verba, C., Beyer, R.A., Geissler, P.E., McEwen, A.S., and the HiRISE Team, 2009. Geology 37, 171-174]. Other observations strongly support the idea of extensive volcanic mudflows (lahars). Evidence for other forms of hydrovolcanism, including glaciovolcanic interactions, is more equivocal. This is largely because most older and high-latitude terrains have been extensively modified, masking any earlier 1-10 m scale features. Much like terrestrial fieldwork, the prerequisite for making full use of HiRISE's capabilities is finding good outcrops.

The iMars WebGIS - Spatio-Temporal Data Queries and Single Image Map Web Services

Science.gov (United States)

Walter, Sebastian; Steikert, Ralf; Schreiner, Bjoern; Muller, Jan-Peter; van Gasselt, Stephan; Sidiropoulos, Panagiotis; Lanz-Kroechert, Julia

2017-04-01

Introduction: Web-based planetary image dissemination platforms usually show outline coverages of the data and offer querying for metadata as well as preview and download, e.g. the HRSC Mapserver (Walter & van Gasselt, 2014). Here we introduce a new approach for a system dedicated to change detection by simultanous visualisation of single-image time series in a multi-temporal context. While the usual form of presenting multi-orbit datasets is the merge of the data into a larger mosaic, we want to stay with the single image as an important snapshot of the planetary surface at a specific time. In the context of the EU FP-7 iMars project we process and ingest vast amounts of automatically co-registered (ACRO) images. The base of the co-registration are the high precision HRSC multi-orbit quadrangle image mosaics, which are based on bundle-block-adjusted multi-orbit HRSC DTMs. Additionally we make use of the existing bundle-adjusted HRSC single images available at the PDS archives. A prototype demonstrating the presented features is available at http://imars.planet.fu-berlin.de. Multi-temporal database: In order to locate multiple coverage of images and select images based on spatio-temporal queries, we converge available coverage catalogs for various NASA imaging missions into a relational database management system with geometry support. We harvest available metadata entries during our processing pipeline using the Integrated Software for Imagers and Spectrometers (ISIS) software. Currently, this database contains image outlines from the MGS/MOC, MRO/CTX and the MO/THEMIS instruments with imaging dates ranging from 1996 to the present. For the MEx/HRSC data, we already maintain a database which we automatically update with custom software based on the VICAR environment. Web Map Service with time support: The MapServer software is connected to the database and provides Web Map Services (WMS) with time support based on the START_TIME image attribute. It allows temporal

Controlled time of arrival windows for already initiated energy-neutral continuous descent operations

OpenAIRE

Dalmau Codina, Ramon; Prats Menéndez, Xavier

2017-01-01

Continuous descent operations with controlled times of arrival at one or several metering fixes could enable environmentally friendly procedures without compromising terminal airspace capacity. This paper focuses on controlled time of arrival updates once the descent has been already initiated, assessing the feasible time window (and associated fuel consumption) of continuous descent operations requiring neither thrust nor speed-brake usage along the whole descent (i.e. only elevator control ...

Entry, Descent, and Landing With Propulsive Deceleration

Science.gov (United States)

Palaszewski, Bryan

2012-01-01

The future exploration of the Solar System will require innovations in transportation and the use of entry, descent, and landing (EDL) systems at many planetary landing sites. The cost of space missions has always been prohibitive, and using the natural planetary and planet s moons atmospheres for entry, descent, and landing can reduce the cost, mass, and complexity of these missions. This paper will describe some of the EDL ideas for planetary entry and survey the overall technologies for EDL that may be attractive for future Solar System missions.

Terrain Safety Assessment in Support of the Mars Science Laboratory Mission

Science.gov (United States)

Kipp, Devin

2012-01-01

In August 2012, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems by delivering the largest and most capable rover to date to the surface of Mars. The process to select the MSL landing site took over five years and began with over 50 initial candidate sites from which four finalist sites were chosen. The four finalist sites were examined in detail to assess overall science merit, EDL safety, and rover traversability on the surface. Ultimately, the engineering assessments demonstrated a high level of safety and robustness at all four finalist sites and differences in the assessment across those sites were small enough that neither EDL safety nor rover traversability considerations could significantly discriminate among the final four sites. Thus the MSL landing site at Gale Crater was selected from among the four finalists primarily on the basis of science considerations.

MetBaro - Pressure Device for Mars MetNet Lander

Science.gov (United States)

Haukka, Harri; Polkko, Jouni; Harri, Ari-Matti; Schmidt, Walter; Leinonen, Jussi; Genzer, Maria; Mäkinen, Teemu

2010-05-01

MetNet Mars Mission focused for Martian atmospheric science is based on a new semihard landing vehicle called the MetNet Lander (MNL). The MNL will have a versatile science payload focused on the atmospheric science of Mars. The scientific payload of the MetNet Mission encompasses separate instrument packages for the atmospheric entry and descent phase and for the surface operation phase. MetBaro is the pressure sensor of MetNet Lander designed to work on Martian surface. It is based on Barocap® technology developed by Vaisala, Inc. MetBaro is a capacitive type of sensing device where capasitor plates are moved by ambient pressure. MetBaro device consists of two pressure transducers including a total of 4 Barocap® sensor heads of high-stability and high-resolution types. The long-term stability of MetBaro is in order of 20…50 µBar and resolution a few µBar. MetBaro is small, lightweighed and has low power consumption. It weighs about 50g without wires and controlling FPGA, and consumes 15 mW of power. A similar device has successfully flown in Phoenix mission, where it performed months of measurements on Martian ground. Another device is also part of the Mars Science Laboratory REMS instrument (to be launched in 2011).

Lunar and Planetary Science XXXV: Mars: Remote Sensing and Terrestrial Analogs

Science.gov (United States)

2004-01-01

The session "Mars: Remote Sensing and Terrestrial Analogs" included the following:Physical Meaning of the Hapke Parameter for Macroscopic Roughness: Experimental Determination for Planetary Regolith Surface Analogs and Numerical Approach; Near-Infrared Spectra of Martian Pyroxene Separates: First Results from Mars Spectroscopy Consortium; Anomalous Spectra of High-Ca Pyroxenes: Correlation Between Ir and M ssbauer Patterns; THEMIS-IR Emissivity Spectrum of a Large Dark Streak near Olympus Mons; Geomorphologic/Thermophysical Mapping of the Athabasca Region, Mars, Using THEMIS Infrared Imaging; Mars Thermal Inertia from THEMIS Data; Multispectral Analysis Methods for Mapping Aqueous Mineral Depostis in Proposed Paleolake Basins on Mars Using THEMIS Data; Joint Analysis of Mars Odyssey THEMIS Visible and Infrared Images: A Magic Airbrush for Qualitative and Quantitative Morphology; Analysis of Mars Thermal Emission Spectrometer Data Using Large Mineral Reference Libraries ; Negative Abundance : A Problem in Compositional Modeling of Hyperspectral Images; Mars-LAB: First Remote Sensing Data of Mineralogy Exposed at Small Mars-Analog Craters, Nevada Test Site; A Tool for the 2003 Rover Mini-TES: Downwelling Radiance Compensation Using Integrated Line-Sight Sky Measurements; Learning About Mars Geology Using Thermal Infrared Spectral Imaging: Orbiter and Rover Perspectives; Classifying Terrestrial Volcanic Alteration Processes and Defining Alteration Processes they Represent on Mars; Cemented Volcanic Soils, Martian Spectra and Implications for the Martian Climate; Palagonitic Mars: A Basalt Centric View of Surface Composition and Aqueous Alteration; Combining a Non Linear Unmixing Model and the Tetracorder Algorithm: Application to the ISM Dataset; Spectral Reflectance Properties of Some Basaltic Weathering Products; Morphometric LIDAR Analysis of Amboy Crater, California: Application to MOLA Analysis of Analog Features on Mars; Airborne Radar Study of Soil Moisture at

EU-FP7-iMars: Analysis of Mars Multi-Resolution Images using Auto-Coregistration, Data Mining and Crowd Source Techniques: One year on with a focus on auto-DTM, auto-coregistration and citizen science.

Science.gov (United States)

Muller, Jan-Peter; Sidiropoulos, Panagiotis; Yershov, Vladimir; Gwinner, Klaus; van Gasselt, Stephan; Walter, Sebastian; Ivanov, Anton; Morley, Jeremy; Sprinks, James; Houghton, Robert; Bamford, Stephen; Kim, Jung-Rack

2015-04-01

Understanding the role of different planetary surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 8 years, especially in 3D imaging of surface shape (down to resolutions of 10cm) and subsequent terrain correction of imagery from orbiting spacecraft. This has led to the ability to be able to overlay different epochs back to the mid-1970s, examine time-varying changes (such as impact craters, RSLs, CO2 geysers, gullies, boulder movements and a host of ice-related phenomena). Consequently we are seeing a dramatic improvement in our understanding of surface formation processes. Since January 2004 the ESA Mars Express has been acquiring global data, especially HRSC stereo (12.5-25m nadir images) with 98% coverage with images ≤100m and more than 70% useful for stereo mapping (e.g. atmosphere sufficiently clear). It has been demonstrated [Gwinner et al., 2010] that HRSC has the highest possible planimetric accuracy of ≤25m and is well co-registered with MOLA, which represents the global 3D reference frame. HRSC 3D and terrain-corrected image products therefore represent the best available 3D reference data for Mars. Recently [Gwinner et al., 2015] have shown the ability to generate mosaiced DTM and BRDF-corrected surface reflectance maps. NASA began imaging the surface of Mars, initially from flybys in the 1960s with the first orbiter with images ≤100m in the late 1970s from Viking Orbiter. The most recent orbiter to begin imaging in November 2006 is the NASA MRO which has acquired surface imagery of around 1% of the Martian surface from HiRISE (at ≈25cm) and ≈5% from CTX (≈6m) in stereo. Unfortunately, for most of these NASA images, especially MGS, MO, VO and HiRISE their accuracy of georeferencing is often worse than the quality of Mars reference data from HRSC. This reduces their value for analysing changes in time

Rationale for a Mars Pathfinder mission to Chryse Planitia and the Viking 1 lander

Science.gov (United States)

Craddock, Robert A.

1994-01-01

Presently the landing site for Mars Pathfinder will be constrained to latitudes between 0 deg and 30 deg N to facilitate communication with earth and to allow the lander and rover solar arrays to generate the maximum possible power. The reference elevation of the site must also be below 0 km so that the descent parachute, a Viking derivative, has sufficient time to open and slow the lander to the correct terminal velocity. Although Mars has as much land surface area as the continental crust of the earth, such engineering constraints immediately limit the number of possible landing sites to only three broad areas: Amazonis, Chryse, and Isidis Planitia. Of these, both Chryse and Isidis Planitia stand out as the sites offering the most information to address several broad scientific topics.

Evolutionary analyses of non-genealogical bonds produced by introgressive descent.

Science.gov (United States)

Bapteste, Eric; Lopez, Philippe; Bouchard, Frédéric; Baquero, Fernando; McInerney, James O; Burian, Richard M

2012-11-06

All evolutionary biologists are familiar with evolutionary units that evolve by vertical descent in a tree-like fashion in single lineages. However, many other kinds of processes contribute to evolutionary diversity. In vertical descent, the genetic material of a particular evolutionary unit is propagated by replication inside its own lineage. In what we call introgressive descent, the genetic material of a particular evolutionary unit propagates into different host structures and is replicated within these host structures. Thus, introgressive descent generates a variety of evolutionary units and leaves recognizable patterns in resemblance networks. We characterize six kinds of evolutionary units, of which five involve mosaic lineages generated by introgressive descent. To facilitate detection of these units in resemblance networks, we introduce terminology based on two notions, P3s (subgraphs of three nodes: A, B, and C) and mosaic P3s, and suggest an apparatus for systematic detection of introgressive descent. Mosaic P3s correspond to a distinct type of evolutionary bond that is orthogonal to the bonds of kinship and genealogy usually examined by evolutionary biologists. We argue that recognition of these evolutionary bonds stimulates radical rethinking of key questions in evolutionary biology (e.g., the relations among evolutionary players in very early phases of evolutionary history, the origin and emergence of novelties, and the production of new lineages). This line of research will expand the study of biological complexity beyond the usual genealogical bonds, revealing additional sources of biodiversity. It provides an important step to a more realistic pluralist treatment of evolutionary complexity.

SU-F-T-427: Utilization and Evaluation of Diagnostic CT Imaging with MAR Technique for Radiation Therapy Treatment Planning

International Nuclear Information System (INIS)

Xu, M; Foster, R; Parks, H; Pankuch, M

2016-01-01

Purpose: The objective was to utilize and evaluate diagnostic CT-MAR technique for radiation therapy treatment planning. Methods: A Toshiba-diagnostic-CT acquisition with SEMAR(Single-energy-MAR)-algorism was performed to make the metal-artifact-reduction (MAR) for patient treatment planning. CT-imaging datasets with and without SEMAR were taken on a Catphan-phantom. Two sets of CT-numbers were calibrated with the relative electron densities (RED). A tissue characterization phantom with Gammex various simulating material rods was used to establish the relationship between known REDs and corresponding CT-numbers. A GE-CT-sim acquisition was taken on the Catphan for comparison. A patient with bilateral hip arthroplasty was scanned in the radiotherapy CT-sim and the diagnostic SEMAR-CT on a flat panel. The derived SEMAR images were used as a primary CT dataset to create contours for the target, critical-structures, and for planning. A deformable registration was performed with VelocityAI to track voxel changes between SEMAR and CT-sim images. The SEMAR-CT images with minimal artifacts and high quality of geometrical and spatial integrity were employed for a treatment plan. Treatment-plans were evaluated based on deformable registration of SEMAR-CT and CT-sim dataset with assigned CT-numbers in the metal artifact regions in Eclipse v11 TPS. Results: The RED and CT-number relationships were consistent for the datasets in CT-sim and CT’s with and without SEMAR. SEMAR datasets with high image quality were used for PTV and organ delineation in the treatment planning process. For dose distribution to the PTV through the DVH analysis, the plan using CT-sim with the assigned CT-number showed a good agreement to those on deformable CT-SEMAR. Conclusion: A diagnostic-CT with MAR-algorithm can be utilized for radiotherapy treatment planning with CT-number calibrated to the RED. Treatment planning comparison and DVH shows a good agreement in the PTV and critical organs between

Enumerating set partitions according to the number of descents of ...

Indian Academy of Sciences (India)

) according to the number of descents of size or more, where ≥ 1 is fixed. An explicit expression in terms of Stirling numbers of the second kind may be given for the total number of such descents in all the members of (,). We also ...

Community tools for cartographic and photogrammetric processing of Mars Express HRSC images

Science.gov (United States)

Kirk, Randolph L.; Howington-Kraus, Elpitha; Edmundson, Kenneth L.; Redding, Bonnie L.; Galuszka, Donna M.; Hare, Trent M.; Gwinner, K.; Wu, B.; Di, K.; Oberst, J.; Karachevtseva, I.

2017-01-01

The High Resolution Stereo Camera (HRSC) on the Mars Express orbiter (Neukum et al. 2004) is a multi-line pushbroom scanner that can obtain stereo and color coverage of targets in a single overpass, with pixel scales as small as 10 m at periapsis. Since commencing operations in 2004 it has imaged ~ 77 % of Mars at 20 m/pixel or better. The instrument team uses the Video Image Communication And Retrieval (VICAR) software to produce and archive a range of data products from uncalibrated and radiometrically calibrated images to controlled digital topographic models (DTMs) and orthoimages and regional mosaics of DTM and orthophoto data (Gwinner et al. 2009; 2010b; 2016). Alternatives to this highly effective standard processing pipeline are nevertheless of interest to researchers who do not have access to the full VICAR suite and may wish to make topographic products or perform other (e. g., spectrophotometric) analyses prior to the release of the highest level products. We have therefore developed software to ingest HRSC images and model their geometry in the USGS Integrated Software for Imagers and Spectrometers (ISIS3), which can be used for data preparation, geodetic control, and analysis, and the commercial photogrammetric software SOCET SET (® BAE Systems; Miller and Walker 1993; 1995) which can be used for independent production of DTMs and orthoimages. The initial implementation of this capability utilized the then-current ISIS2 system and the generic pushbroom sensor model of SOCET SET, and was described in the DTM comparison of independent photogrammetric processing by different elements of the HRSC team (Heipke et al. 2007). A major drawback of this prototype was that neither software system then allowed for pushbroom images in which the exposure time changes from line to line. Except at periapsis, HRSC makes such timing changes every few hundred lines to accommodate changes of altitude and velocity in its elliptical orbit. As a result, it was

First Grinding of a Rock on Mars

Science.gov (United States)

2004-01-01

The round, shallow depression in this image resulted from history's first grinding of a rock on Mars. The rock abrasion tool on NASA's Spirit rover ground off the surface of a patch 45.5 millimeters (1.8 inches) in diameter on a rock called Adirondack during Spirit's 34th sol on Mars, Feb. 6, 2004. The hole is 2.65 millimeters (0.1 inch) deep, exposing fresh interior material of the rock for close inspection with the rover's microscopic imager and two spectrometers on the robotic arm. This image was taken by Spirit's panoramic camera, providing a quick visual check of the success of the grinding. The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.

Accelerating deep neural network training with inconsistent stochastic gradient descent.

Science.gov (United States)

Wang, Linnan; Yang, Yi; Min, Renqiang; Chakradhar, Srimat

2017-09-01

Stochastic Gradient Descent (SGD) updates Convolutional Neural Network (CNN) with a noisy gradient computed from a random batch, and each batch evenly updates the network once in an epoch. This model applies the same training effort to each batch, but it overlooks the fact that the gradient variance, induced by Sampling Bias and Intrinsic Image Difference, renders different training dynamics on batches. In this paper, we develop a new training strategy for SGD, referred to as Inconsistent Stochastic Gradient Descent (ISGD) to address this problem. The core concept of ISGD is the inconsistent training, which dynamically adjusts the training effort w.r.t the loss. ISGD models the training as a stochastic process that gradually reduces down the mean of batch's loss, and it utilizes a dynamic upper control limit to identify a large loss batch on the fly. ISGD stays on the identified batch to accelerate the training with additional gradient updates, and it also has a constraint to penalize drastic parameter changes. ISGD is straightforward, computationally efficient and without requiring auxiliary memories. A series of empirical evaluations on real world datasets and networks demonstrate the promising performance of inconsistent training. Copyright © 2017 Elsevier Ltd. All rights reserved.

Momentum-weighted conjugate gradient descent algorithm for gradient coil optimization.

Science.gov (United States)

Lu, Hanbing; Jesmanowicz, Andrzej; Li, Shi-Jiang; Hyde, James S

2004-01-01

MRI gradient coil design is a type of nonlinear constrained optimization. A practical problem in transverse gradient coil design using the conjugate gradient descent (CGD) method is that wire elements move at different rates along orthogonal directions (r, phi, z), and tend to cross, breaking the constraints. A momentum-weighted conjugate gradient descent (MW-CGD) method is presented to overcome this problem. This method takes advantage of the efficiency of the CGD method combined with momentum weighting, which is also an intrinsic property of the Levenberg-Marquardt algorithm, to adjust step sizes along the three orthogonal directions. A water-cooled, 12.8 cm inner diameter, three axis torque-balanced gradient coil for rat imaging was developed based on this method, with an efficiency of 2.13, 2.08, and 4.12 mT.m(-1).A(-1) along X, Y, and Z, respectively. Experimental data demonstrate that this method can improve efficiency by 40% and field uniformity by 27%. This method has also been applied to the design of a gradient coil for the human brain, employing remote current return paths. The benefits of this design include improved gradient field uniformity and efficiency, with a shorter length than gradient coil designs using coaxial return paths. Copyright 2003 Wiley-Liss, Inc.

Mars Science Laboratory Differential Restraint: The Devil is in the Details

Science.gov (United States)

Jordan, Elizabeth

2012-01-01

The Differential Restraint, a mechanism used on the Mars Science Laboratory (MSL) rover to maintain symmetry of the mobility system during the launch, cruise, and entry descent and landing phases of the MSL mission, completed nearly three full design cycles before a finalized successful design was achieved. This paper address the lessons learned through these design cycles, including three major design elements that can easily be overlooked during the design process, including, tolerance stack contribution to load path, the possibility of Martian dirt as a failure mode, and the effects of material properties at temperature extremes.

Testicular descent: INSL3, testosterone, genes and the intrauterine milieu

DEFF Research Database (Denmark)

Bay, Katrine; Main, Katharina M; Toppari, Jorma

2011-01-01

Complete testicular descent is a sign of, and a prerequisite for, normal testicular function in adult life. The process of testis descent is dependent on gubernacular growth and reorganization, which is regulated by the Leydig cell hormones insulin-like peptide 3 (INSL3) and testosterone. Investi...

Reactive Sequencing for Autonomous Navigation Evolving from Phoenix Entry, Descent, and Landing

Science.gov (United States)

Grasso, Christopher A.; Riedel, Joseph E.; Vaughan, Andrew T.

2010-01-01

Virtual Machine Language (VML) is an award-winning advanced procedural sequencing language in use on NASA deep-space missions since 1997, and was used for the successful entry, descent, and landing (EDL) of the Phoenix spacecraft onto the surface of Mars. Phoenix EDL utilized a state-oriented operations architecture which executed within the constraints of the existing VML 2.0 flight capability, compatible with the linear "land or die" nature of the mission. The intricacies of Phoenix EDL included the planned discarding of portions of the vehicle, the complex communications management for relay through on-orbit assets, the presence of temporally indeterminate physical events, and the need to rapidly catch up four days of sequencing should a reboot of the spacecraft flight computer occur shortly before atmospheric entry. These formidable operational challenges led to new techniques for packaging and coordinating reusable sequences called blocks using one-way synchronization via VML sequencing global variable events. The coordinated blocks acted as an ensemble to land the spacecraft, while individually managing various elements in as simple a fashion as possible. This paper outlines prototype VML 2.1 flight capabilities that have evolved from the one-way synchronization techniques in order to implement even more ambitious autonomous mission capabilities. Target missions for these new capabilities include autonomous touch-and-go sampling of cometary and asteroidal bodies, lunar landing of robotic missions, and ultimately landing of crewed lunar vehicles. Close proximity guidance, navigation, and control operations, on-orbit rendezvous, and descent and landing events featured in these missions require elaborate abort capability, manifesting highly non-linear scenarios that are so complex as to overtax traditional sequencing, or even the sort of one-way coordinated sequencing used during EDL. Foreseeing advanced command and control needs for small body and lunar landing

Steepest descent method implementation on unconstrained optimization problem using C++ program

Science.gov (United States)

Napitupulu, H.; Sukono; Mohd, I. Bin; Hidayat, Y.; Supian, S.

2018-03-01

Steepest Descent is known as the simplest gradient method. Recently, many researches are done to obtain the appropriate step size in order to reduce the objective function value progressively. In this paper, the properties of steepest descent method from literatures are reviewed together with advantages and disadvantages of each step size procedure. The development of steepest descent method due to its step size procedure is discussed. In order to test the performance of each step size, we run a steepest descent procedure in C++ program. We implemented it to unconstrained optimization test problem with two variables, then we compare the numerical results of each step size procedure. Based on the numerical experiment, we conclude the general computational features and weaknesses of each procedure in each case of problem.

Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells

Science.gov (United States)

Alkandry, Hicham

Future missions to Mars, including sample-return and human-exploration missions, may require alternative entry, descent, and landing technologies in order to perform pinpoint landing of heavy vehicles. Two such alternatives are propulsive deceleration (PD) and reaction control systems (RCS). PD can slow the vehicle during Mars atmospheric descent by directing thrusters into the incoming freestream. RCS can provide vehicle control and steering by inducing moments using thrusters on the hack of the entry capsule. The use of these PD and RCS jets, however, involves complex flow interactions that are still not well understood. The fluid interactions induced by PD and RCS jets for Mars-entry vehicles in hypersonic freestream conditions are investigated using computational fluid dynamics (CFD). The effects of central and peripheral PD configurations using both sonic and supersonic jets at various thrust conditions are examined in this dissertation. The RCS jet is directed either parallel or transverse to the freestream flow at different thrust conditions in order to examine the effects of the thruster orientation with respect to the center of gravity of the aeroshell. The physical accuracy of the computational method is also assessed by comparing the numerical results with available experimental data. The central PD configuration decreases the drag force acting on the entry capsule due to a shielding effect that prevents mass and momentum in the hypersonic freestream from reaching the aeroshell. The peripheral PD configuration also decreases the drag force by obstructing the flow around the aeroshell and creating low surface pressure regions downstream of the PD nozzles. The Mach number of the PD jets, however, does not have a significant effect on the induced fluid interactions. The reaction control system also alters the flowfield, surface, and aerodynamic properties of the aeroshell, while the jet orientation can have a significant effect on the control effectiveness

Community Tools for Cartographic and Photogrammetric Processing of Mars Express HRSC Images

Science.gov (United States)

Kirk, R. L.; Howington-Kraus, E.; Edmundson, K.; Redding, B.; Galuszka, D.; Hare, T.; Gwinner, K.

2017-07-01

The High Resolution Stereo Camera (HRSC) on the Mars Express orbiter (Neukum et al. 2004) is a multi-line pushbroom scanner that can obtain stereo and color coverage of targets in a single overpass, with pixel scales as small as 10 m at periapsis. Since commencing operations in 2004 it has imaged  77 % of Mars at 20 m/pixel or better. The instrument team uses the Video Image Communication And Retrieval (VICAR) software to produce and archive a range of data products from uncalibrated and radiometrically calibrated images to controlled digital topographic models (DTMs) and orthoimages and regional mosaics of DTM and orthophoto data (Gwinner et al. 2009; 2010b; 2016). Alternatives to this highly effective standard processing pipeline are nevertheless of interest to researchers who do not have access to the full VICAR suite and may wish to make topographic products or perform other (e. g., spectrophotometric) analyses prior to the release of the highest level products. We have therefore developed software to ingest HRSC images and model their geometry in the USGS Integrated Software for Imagers and Spectrometers (ISIS3), which can be used for data preparation, geodetic control, and analysis, and the commercial photogrammetric software SOCET SET (® BAE Systems; Miller and Walker 1993; 1995) which can be used for independent production of DTMs and orthoimages. The initial implementation of this capability utilized the then-current ISIS2 system and the generic pushbroom sensor model of SOCET SET, and was described in the DTM comparison of independent photogrammetric processing by different elements of the HRSC team (Heipke et al. 2007). A major drawback of this prototype was that neither software system then allowed for pushbroom images in which the exposure time changes from line to line. Except at periapsis, HRSC makes such timing changes every few hundred lines to accommodate changes of altitude and velocity in its elliptical orbit. As a result, it was

COMMUNITY TOOLS FOR CARTOGRAPHIC AND PHOTOGRAMMETRIC PROCESSING OF MARS EXPRESS HRSC IMAGES

Directory of Open Access Journals (Sweden)

R. L. Kirk

2017-07-01

Full Text Available The High Resolution Stereo Camera (HRSC on the Mars Express orbiter (Neukum et al. 2004 is a multi-line pushbroom scanner that can obtain stereo and color coverage of targets in a single overpass, with pixel scales as small as 10 m at periapsis. Since commencing operations in 2004 it has imaged ~ 77 % of Mars at 20 m/pixel or better. The instrument team uses the Video Image Communication And Retrieval (VICAR software to produce and archive a range of data products from uncalibrated and radiometrically calibrated images to controlled digital topographic models (DTMs and orthoimages and regional mosaics of DTM and orthophoto data (Gwinner et al. 2009; 2010b; 2016. Alternatives to this highly effective standard processing pipeline are nevertheless of interest to researchers who do not have access to the full VICAR suite and may wish to make topographic products or perform other (e. g., spectrophotometric analyses prior to the release of the highest level products. We have therefore developed software to ingest HRSC images and model their geometry in the USGS Integrated Software for Imagers and Spectrometers (ISIS3, which can be used for data preparation, geodetic control, and analysis, and the commercial photogrammetric software SOCET SET (® BAE Systems; Miller and Walker 1993; 1995 which can be used for independent production of DTMs and orthoimages. The initial implementation of this capability utilized the then-current ISIS2 system and the generic pushbroom sensor model of SOCET SET, and was described in the DTM comparison of independent photogrammetric processing by different elements of the HRSC team (Heipke et al. 2007. A major drawback of this prototype was that neither software system then allowed for pushbroom images in which the exposure time changes from line to line. Except at periapsis, HRSC makes such timing changes every few hundred lines to accommodate changes of altitude and velocity in its elliptical orbit. As a result

Technical Note: FreeCT_ICD: An Open Source Implementation of a Model-Based Iterative Reconstruction Method using Coordinate Descent Optimization for CT Imaging Investigations.

Science.gov (United States)

Hoffman, John M; Noo, Frédéric; Young, Stefano; Hsieh, Scott S; McNitt-Gray, Michael

2018-06-01

To facilitate investigations into the impacts of acquisition and reconstruction parameters on quantitative imaging, radiomics and CAD using CT imaging, we previously released an open source implementation of a conventional weighted filtered backprojection reconstruction called FreeCT_wFBP. Our purpose was to extend that work by providing an open-source implementation of a model-based iterative reconstruction method using coordinate descent optimization, called FreeCT_ICD. Model-based iterative reconstruction offers the potential for substantial radiation dose reduction, but can impose substantial computational processing and storage requirements. FreeCT_ICD is an open source implementation of a model-based iterative reconstruction method that provides a reasonable tradeoff between these requirements. This was accomplished by adapting a previously proposed method that allows the system matrix to be stored with a reasonable memory requirement. The method amounts to describing the attenuation coefficient using rotating slices that follow the helical geometry. In the initially-proposed version, the rotating slices are themselves described using blobs. We have replaced this description by a unique model that relies on tri-linear interpolation together with the principles of Joseph's method. This model offers an improvement in memory requirement while still allowing highly accurate reconstruction for conventional CT geometries. The system matrix is stored column-wise and combined with an iterative coordinate descent (ICD) optimization. The result is FreeCT_ICD, which is a reconstruction program developed on the Linux platform using C++ libraries and the open source GNU GPL v2.0 license. The software is capable of reconstructing raw projection data of helical CT scans. In this work, the software has been described and evaluated by reconstructing datasets exported from a clinical scanner which consisted of an ACR accreditation phantom dataset and a clinical pediatric

Scientific Payload Of The Emirates Mars Mission: Emirates Mars Infrared Spectrometer (Emirs) Overview.

Science.gov (United States)

Altunaiji, E. S.; Edwards, C. S.; Christensen, P. R.; Smith, M. D.; Badri, K. M., Sr.

2017-12-01

The Emirates Mars Mission (EMM) will launch in 2020 to explore the dynamics in the atmosphere of Mars on a global scale. EMM has three scientific instruments to an improved understanding of circulation and weather in the Martian lower and middle atmosphere. Two of the EMM's instruments, which are the Emirates eXploration Imager (EXI) and Emirates Mars Infrared Spectrometer (EMIRS) will focus on the lower atmosphere observing dust, ice clouds, water vapor and ozone. On the other hand, the third instrument Emirates Mars Ultraviolet Spectrometer (EMUS) will focus on both the thermosphere of the planet and its exosphere. The EMIRS instrument, shown in Figure 1, is an interferometric thermal infrared spectrometer that is jointly developed by Arizona State University (ASU) and Mohammed Bin Rashid Space Centre (MBRSC). It builds on a long heritage of thermal infrared spectrometers designed, built, and managed, by ASU's Mars Space Flight Facility, including the Thermal Emission Spectrometer (TES), Miniature Thermal Emission Spectrometer (Mini-TES), and the OSIRIS-REx Thermal Emission Spectrometer (OTES). EMIRS operates in the 6-40+ µm range with 5 cm-1 spectral sampling, enabled by a Chemical Vapor-Deposited (CVD) diamond beamsplitter and state of the art electronics. This instrument utilizes a 3×3 detector array and a scan mirror to make high-precision infrared radiance measurements over most of a Martian hemisphere. The EMIRS instrument is optimized to capture the integrated, lower-middle atmosphere dynamics over a Martian hemisphere and will capture 60 global images per week ( 20 images per orbit) at a resolution of 100-300 km/pixel. After processing through an atmospheric retrieval algorithm, EMIRS will determine the vertical temperature profiles to 50km altitude and measure the column integrated global distribution and abundances of key atmospheric parameters (e.g. dust, water ice (clouds) and water vapor) over the Martian day, seasons and year.

Elemental Composition of Mars Return Samples Using X-Ray Fluorescence Imaging at the National Synchrotron Light Source II

Science.gov (United States)

Thieme, J.; Hurowitz, J. A.; Schoonen, M. A.; Fogelqvist, E.; Gregerson, J.; Farley, K. A.; Sherman, S.; Hill, J.

2018-04-01

NSLS-II at BNL provides a unique and critical capability to perform assessments of the elemental composition and the chemical state of Mars returned samples using synchrotron radiation X-ray fluorescence imaging and X-ray absorption spectroscopy.

Optimization of the alpha image reconstruction. An iterative CT-image reconstruction with well-defined image quality metrics

Energy Technology Data Exchange (ETDEWEB)

Lebedev, Sergej; Sawall, Stefan; Knaup, Michael; Kachelriess, Marc [German Cancer Research Center, Heidelberg (Germany).

2017-10-01

Optimization of the AIR-algorithm for improved convergence and performance. TThe AIR method is an iterative algorithm for CT image reconstruction. As a result of its linearity with respect to the basis images, the AIR algorithm possesses well defined, regular image quality metrics, e.g. point spread function (PSF) or modulation transfer function (MTF), unlike other iterative reconstruction algorithms. The AIR algorithm computes weighting images α to blend between a set of basis images that preferably have mutually exclusive properties, e.g. high spatial resolution or low noise. The optimized algorithm uses an approach that alternates between the optimization of rawdata fidelity using an OSSART like update and regularization using gradient descent, as opposed to the initially proposed AIR using a straightforward gradient descent implementation. A regularization strength for a given task is chosen by formulating a requirement for the noise reduction and checking whether it is fulfilled for different regularization strengths, while monitoring the spatial resolution using the voxel-wise defined modulation transfer function for the AIR image. The optimized algorithm computes similar images in a shorter time compared to the initial gradient descent implementation of AIR. The result can be influenced by multiple parameters that can be narrowed down to a relatively simple framework to compute high quality images. The AIR images, for instance, can have at least a 50% lower noise level compared to the sharpest basis image, while the spatial resolution is mostly maintained. The optimization improves performance by a factor of 6, while maintaining image quality. Furthermore, it was demonstrated that the spatial resolution for AIR can be determined using regular image quality metrics, given smooth weighting images. This is not possible for other iterative reconstructions as a result of their non linearity. A simple set of parameters for the algorithm is discussed that provides

Optimization of the alpha image reconstruction. An iterative CT-image reconstruction with well-defined image quality metrics

International Nuclear Information System (INIS)

Lebedev, Sergej; Sawall, Stefan; Knaup, Michael; Kachelriess, Marc

2017-01-01

Optimization of the AIR-algorithm for improved convergence and performance. TThe AIR method is an iterative algorithm for CT image reconstruction. As a result of its linearity with respect to the basis images, the AIR algorithm possesses well defined, regular image quality metrics, e.g. point spread function (PSF) or modulation transfer function (MTF), unlike other iterative reconstruction algorithms. The AIR algorithm computes weighting images α to blend between a set of basis images that preferably have mutually exclusive properties, e.g. high spatial resolution or low noise. The optimized algorithm uses an approach that alternates between the optimization of rawdata fidelity using an OSSART like update and regularization using gradient descent, as opposed to the initially proposed AIR using a straightforward gradient descent implementation. A regularization strength for a given task is chosen by formulating a requirement for the noise reduction and checking whether it is fulfilled for different regularization strengths, while monitoring the spatial resolution using the voxel-wise defined modulation transfer function for the AIR image. The optimized algorithm computes similar images in a shorter time compared to the initial gradient descent implementation of AIR. The result can be influenced by multiple parameters that can be narrowed down to a relatively simple framework to compute high quality images. The AIR images, for instance, can have at least a 50% lower noise level compared to the sharpest basis image, while the spatial resolution is mostly maintained. The optimization improves performance by a factor of 6, while maintaining image quality. Furthermore, it was demonstrated that the spatial resolution for AIR can be determined using regular image quality metrics, given smooth weighting images. This is not possible for other iterative reconstructions as a result of their non linearity. A simple set of parameters for the algorithm is discussed that provides

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.

Mars Mission Concepts: SAR and Solar Electric Propulsion

Science.gov (United States)

Elsperman, M.; Klaus, K.; Smith, D. B.; Clifford, S. M.; Lawrence, S. J.

2012-12-01

Introduction: The time has come to leverage technology advances (including advances in autonomous operation and propulsion technology) to reduce the cost and increase the flight rate of planetary missions, while actively developing a scientific and engineering workforce to achieve national space objectives. Mission Science at Mars: A SAR imaging radar offers an ability to conduct high resolution investigations of the shallow (Models uniquely useful for exploration planning and science purposes. Since the SAR and the notional high-resolution stereo imaging system would be huge data volume producers - to maximize the science return we are currently considering the usage of laser communications systems; this notional spacecraft represents one pathway to evaluate the utility of laser communications in planetary exploration while providing useful science return.. Mission Concept: Using a common space craft for multiple missions reduces costs. Solar electric propulsion (SEP) provides the flexibility required for multiple mission objectives. SEP provides the greatest payload advantage albeit at the sacrifice of mission time. Our concept involves using a SEP enabled space craft (Boeing 702SP) with a highly capable SAR imager that also conducts autonomous rendezvous and docking experiments accomplished from Mars orbit. Our concept of operations is to launch on May 5, 2018 using a launch vehicle with 2000kg launch capacity with a C3 of 7.4. After reaching Mars it takes 145 days to spiral down to a 250 km orbit above the surface of Mars when Mars SAR operations begin. Summary/Conclusions: A robust and compelling Mars mission can be designed to meet the 2018 Mars launch window opportunity. Using advanced in-space power and propulsion technologies like High Power Solar Electric Propulsion provides enormous mission flexibility to execute the baseline science mission and conduct necessary Mars Sample Return Technology Demonstrations in Mars orbit on the same mission. An

Calibration OGSEs for multichannel radiometers for Mars atmosphere studies

Science.gov (United States)

Jiménez, J. J.; J Álvarez, F.; Gonzalez-Guerrero, M.; Apéstigue, V.; Martín, I.; Fernández, J. M.; Fernán, A. A.; Arruego, I.

2018-06-01

This work describes several Optical Ground Support Equipment (OGSEs) developed by INTA (Spanish Institute of Aerospace Technology—Instituto Nacional de Técnica Aeroespacial) for the calibration and characterization of their self-manufactured multichannel radiometers (solar irradiance sensors—SIS) developed for working on the surface of Mars and studying the atmosphere of that planet. Nowadays, INTA is developing two SIS for the ESA ExoMars 2020 and for the JPL/NASA Mars 2020 missions. These calibration OGSEs have been improved since the first model in 2011 developed for Mars MetNet Precursor mission. This work describes the currently used OGSE. Calibration tests provide an objective evidence of the SIS performance, allowing the conversion of the electrical sensor output into accurate physical measurements (irradiance) with uncertainty bounds. Calibration results of the SIS on board of the Dust characterisation, Risk assessment, and Environment Analyzer on the Martian Surface (DREAMS) on board the ExoMars 2016 Schiaparelli module (EDM—entry and descent module) are also presented, as well as their error propagation. Theoretical precision and accuracy of the instrument are determined by these results. Two types of OGSE are used as a function of the pursued aim: calibration OGSEs and Optical Fast Verification (OFV) GSE. Calibration OGSEs consist of three setups which characterize with the highest possible accuracy, the responsivity, the angular response and the thermal behavior; OFV OGSE verify that the performance of the sensor is close to nominal after every environmental and qualification test. Results show that the accuracy of the calibrated sensors is a function of the accuracy of the optical detectors and of the light conditions. For normal direct incidence and diffuse light, the accuracy is in the same order of uncertainty as that of the reference cell used for fixing the irradiance, which is about 1%.

Calibration OGSEs for multichannel radiometers for Mars atmosphere studies

Science.gov (United States)

Jiménez, J. J.; J Álvarez, F.; Gonzalez-Guerrero, M.; Apéstigue, V.; Martín, I.; Fernández, J. M.; Fernán, A. A.; Arruego, I.

2018-02-01

This work describes several Optical Ground Support Equipment (OGSEs) developed by INTA (Spanish Institute of Aerospace Technology—Instituto Nacional de Técnica Aeroespacial) for the calibration and characterization of their self-manufactured multichannel radiometers (solar irradiance sensors—SIS) developed for working on the surface of Mars and studying the atmosphere of that planet. Nowadays, INTA is developing two SIS for the ESA ExoMars 2020 and for the JPL/NASA Mars 2020 missions. These calibration OGSEs have been improved since the first model in 2011 developed for Mars MetNet Precursor mission. This work describes the currently used OGSE. Calibration tests provide an objective evidence of the SIS performance, allowing the conversion of the electrical sensor output into accurate physical measurements (irradiance) with uncertainty bounds. Calibration results of the SIS on board of the Dust characterisation, Risk assessment, and Environment Analyzer on the Martian Surface (DREAMS) on board the ExoMars 2016 Schiaparelli module (EDM—entry and descent module) are also presented, as well as their error propagation. Theoretical precision and accuracy of the instrument are determined by these results. Two types of OGSE are used as a function of the pursued aim: calibration OGSEs and Optical Fast Verification (OFV) GSE. Calibration OGSEs consist of three setups which characterize with the highest possible accuracy, the responsivity, the angular response and the thermal behavior; OFV OGSE verify that the performance of the sensor is close to nominal after every environmental and qualification test. Results show that the accuracy of the calibrated sensors is a function of the accuracy of the optical detectors and of the light conditions. For normal direct incidence and diffuse light, the accuracy is in the same order of uncertainty as that of the reference cell used for fixing the irradiance, which is about 1%.

Reduction of dental metallic artefacts in CT: Value of a newly developed algorithm for metal artefact reduction (O-MAR)

International Nuclear Information System (INIS)

Kidoh, M.; Nakaura, T.; Nakamura, S.; Tokuyasu, S.; Osakabe, H.; Harada, K.; Yamashita, Y.

2014-01-01

Aim: To evaluate the image quality of O-MAR (Metal Artifact Reduction for Orthopedic Implants) for dental metal artefact reduction. Materials and methods: This prospective study received institutional review board approval and written informed consent was obtained. Thirty patients who had dental implants or dental fillings were included in this study. Computed tomography (CT) images were obtained through the oral cavity and neck during the portal venous phase. The system reconstructed the O-MAR-processed images in addition to the uncorrected images. CT attenuation and image noise of the soft tissue of the oral cavity were compared between the O-MAR and the uncorrected images. Qualitative analysis was undertaken between the two image groups. Results: The image noise of the O-MAR images was significantly lower than that of the uncorrected images (p < 0.01). O-MAR offered plausible attenuations of soft tissue compared with non-O-MAR. Better qualitative scores were obtained in the streaking artefacts and the degree of depiction of the oral cavity with O-MAR compared with non-O-MAR. Conclusion: O-MAR enables the depiction of structures in areas in which this was not previously possible due to dental metallic artefacts in qualitative image analysis. O-MAR images may have a supplementary role in addition to uncorrected images in oral diagnosis

Protection of surface assets on Mars from wind blown jettisoned spacecraft components

Science.gov (United States)

Paton, Mark

2017-07-01

Jettisoned Entry, Descent and Landing System (EDLS) hardware from landing spacecraft have been observed by orbiting spacecraft, strewn over the Martian surface. Future Mars missions that land spacecraft close to prelanded assets will have to use a landing architecture that somehow minimises the possibility of impacts from these jettisoned EDLS components. Computer modelling is used here to investigate the influence of wind speed and direction on the distribution of EDLS components on the surface. Typical wind speeds encountered in the Martian Planetary Boundary Layer (PBL) were found to be of sufficient strength to blow items having a low ballistic coefficient, i.e. Hypersonic Inflatable Aerodynamic Decelerators (HIADs) or parachutes, onto prelanded assets even when the lander itself touches down several kilometres away. Employing meteorological measurements and careful characterisation of the Martian PBL, e.g. appropriate wind speed probability density functions, may then benefit future spacecraft landings, increase safety and possibly help reduce the delta v budget for Mars landers that rely on aerodynamic decelerators.

Mars MetNet Mission - Martian Atmospheric Observational Post Network

Science.gov (United States)

Hari, Ari-Matti; Haukka, Harri; Aleksashkin, Sergey; Arruego, Ignacio; Schmidt, Walter; Genzer, Maria; Vazquez, Luis; Siikonen, Timo; Palin, Matti

2017-04-01

A new kind of planetary exploration mission for Mars is under development in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semi-hard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor [1] mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide significant insights in to the Martian atmospheric behavior. The key technologies of the MetNet Lander have been qualified and the electrical qualification model (EQM) of the payload bay has been built and successfully tested. 1. MetNet Lander The MetNet landing vehicles are using an inflatable entry and descent system instead of rigid heat shields and parachutes as earlier semi-hard landing devices have used. This way the ratio of the payload mass to the overall mass is optimized. The landing impact will burrow the payload container into the Martian soil providing a more favorable thermal environment for the electronics and a suitable orientation of the telescopic boom with external sensors and the radio link antenna. It is planned to deploy several tens of MNLs on the Martian surface operating at least partly at the same time to allow meteorological network science. 2. Strawman Scientific Payload The strawman payload of the two MNL precursor models includes the following instruments: Atmospheric instruments: - MetBaro Pressure device - MetHumi Humidity device - MetTemp Temperature sensors Optical devices: - PanCam Panoramic - MetSIS Solar irradiance sensor with OWLS optical wireless system for data transfer - DS Dust sensor Composition and Structure Devices: Tri-axial magnetometer MOURA Tri-axial System Accelerometer The descent processes dynamic properties are monitored by a special 3-axis

A Risk-Constrained Multi-Stage Decision Making Approach to the Architectural Analysis of Mars Missions

Science.gov (United States)

Kuwata, Yoshiaki; Pavone, Marco; Balaram, J. (Bob)

2012-01-01

This paper presents a novel risk-constrained multi-stage decision making approach to the architectural analysis of planetary rover missions. In particular, focusing on a 2018 Mars rover concept, which was considered as part of a potential Mars Sample Return campaign, we model the entry, descent, and landing (EDL) phase and the rover traverse phase as four sequential decision-making stages. The problem is to find a sequence of divert and driving maneuvers so that the rover drive is minimized and the probability of a mission failure (e.g., due to a failed landing) is below a user specified bound. By solving this problem for several different values of the model parameters (e.g., divert authority), this approach enables rigorous, accurate and systematic trade-offs for the EDL system vs. the mobility system, and, more in general, cross-domain trade-offs for the different phases of a space mission. The overall optimization problem can be seen as a chance-constrained dynamic programming problem, with the additional complexity that 1) in some stages the disturbances do not have any probabilistic characterization, and 2) the state space is extremely large (i.e, hundreds of millions of states for trade-offs with high-resolution Martian maps). To this purpose, we solve the problem by performing an unconventional combination of average and minimax cost analysis and by leveraging high efficient computation tools from the image processing community. Preliminary trade-off results are presented.

MarsSI: Martian surface data processing information system

Science.gov (United States)

Quantin-Nataf, C.; Lozac'h, L.; Thollot, P.; Loizeau, D.; Bultel, B.; Fernando, J.; Allemand, P.; Dubuffet, F.; Poulet, F.; Ody, A.; Clenet, H.; Leyrat, C.; Harrisson, S.

2018-01-01

MarsSI (Acronym for Mars System of Information, https://emars.univ-lyon1.fr/MarsSI/, is a web Geographic Information System application which helps managing and processing martian orbital data. The MarsSI facility is part of the web portal called PSUP (Planetary SUrface Portal) developed by the Observatories of Paris Sud (OSUPS) and Lyon (OSUL) to provide users with efficient and easy access to data products dedicated to the martian surface. The portal proposes 1) the management and processing of data thanks to MarsSI and 2) the visualization and merging of high level (imagery, spectral, and topographic) products and catalogs via a web-based user interface (MarsVisu). The portal PSUP as well as the facility MarsVisu is detailed in a companion paper (Poulet et al., 2018). The purpose of this paper is to describe the facility MarsSI. From this application, users are able to easily and rapidly select observations, process raw data via automatic pipelines, and get back final products which can be visualized under Geographic Information Systems. Moreover, MarsSI also contains an automatic stereo-restitution pipeline in order to produce Digital Terrain Models (DTM) on demand from HiRISE (High Resolution Imaging Science Experiment) or CTX (Context Camera) pair-images. This application is funded by the European Union's Seventh Framework Programme (FP7/2007-2013) (ERC project eMars, No. 280168) and has been developed in the scope of Mars, but the design is applicable to any other planetary body of the solar system.

Characterization of Medipix3 with the MARS readout and software

CERN Document Server

Ronaldson, J P; van Leeuwen, D; Doesburg, R M N; Ballabriga, R; Butler, A P H; Donaldson, J; Walsh, M; Nik, S J; Clyne, M N

2011-01-01

The Medipix3 x-ray imaging detector has been characterized using the MARS camera. This x-ray camera comprises custom built readout electronics and software libraries designed for the Medipix family of detectors. The performance of the Medipix3 and MARS camera system is being studied prior to use in real-world applications such as the recently developed MARS-CT3 spectroscopic micro-CT scanner. We present the results of characterization measurements, describe methods for optimizing performance and give examples of spectroscopic images acquired with Medipix3 and the MARS camera system. A limited number of operating modes of the Medipix3 chip have been characterized and single-pixel mode has been found to give acceptable performance in terms of energy response, image quality and stability over time. Spectroscopic performance is significantly better in charge-summing mode than single-pixel mode however image quality and stability over time are compromised. There are more modes of operation to be tested and further...

THE GREAT DESCENT CONTINUES

CERN Document Server

    With precise coordination YE+1 was lowered into the cavern (9-Jan), soon joined by the ?rst barrel wheel YB+2 (19-Jan), then YB+1(4-Feb) and HB+ (13-Feb). The 1920 ton central barrel wheel YB0 rests brie?y on the pit-head cover in anticipation of a monumental descent (28-Feb) that will also trigger an intense campaign of installation of services and detectors underground.  

EU-FP7-iMARS: analysis of Mars multi-resolution images using auto-coregistration, data mining and crowd source techniques: A Status Report

Science.gov (United States)

Muller, Jan-Peter; Sidiropoulos, Panagiotis; Tao, Yu; Gwinner, Klaus; Willner, Konrad; Fanara, Lida; Waehlisch, Marita; Walter, Sebastian; Schreiner, Bjoern; Steikert, Ralf; Ivanov, Anton B.; Cantini, Federico; Wardlaw, Jessica; Sprinks, James Christopher; Giordano, Michele; Kim, Jungrack; Houghton, Robert; Bamford, Steven

2016-10-01

There has been a revolution in 3D surface imaging of Mars over the last 12 years with systematic stereoscopy from HRSC and the production for almost 50% of the Martian surface of DTMs and ORIs. The iMars project has been exploiting this unique set of 3D products as a basemap to co-register NASA imagery going back to the 1970s. DLR have produced 3D HRSC mosaic products for large regions with c. 100 individual strips/region (MC-11E/W). UCL have developed an automated processing chain for CTX and HiRISE 3D processing to densify this global HRSC dataset with DTMs down to 18m and 75cm respectively [1]. A fully Automated Co-Registration and Orthorectification (ACRO) system has been developed at UCL and applied to the production of around 8,000 images co-registered to a HRSC pixel (typically 12.5m) and orthorectified to HRSC DTMs of 50-150m spacing [2]. These images are viewable through an OGC-compliant webGIS developed at FUB including tools for viewing sequences over the same area [3]. Corresponding MARSIS and SHARAD data can be viewed through the QGIS plugin available [4]. An automated data mining system is being developed at UCL [5] for change detection to search and classify features in images going back to Viking Orbiter of IFoV ≤100m. In parallel, a citizen science project at Nottingham University [6] is defining training samples for classification of change features and eventually for verification of change [7]. Scientific applications include change mapping over the SPRC [8], mass movements near the North Pole [9]; dark streaks [10] CRISM mapping of mineralogy of dust in the SPRC "Swiss cheese" layers [11] and mapping of dune movement [12]. [1] Tao, Y. & J.-P. Muller LPSC16-2074; [2] Gwinner, K. et al. EPSC15-672; [3] van Gasselt, S. et al. EPSC14-693; [4] Ivanov, A. & Cantini, F. EPSC16; [5] Sidiropoulos, P. & J.-P. Muller EPSC16; [6] Sprinks et al. EPSC16; [7] Wardlaw et al. EPSC16; [8] Putri et al., EPSC16;[9] Fanara, L. et al. EPSC 16; [10] Schreiner, B. et

Dictionary descent in optimization

OpenAIRE

Temlyakov, Vladimir

2015-01-01

The problem of convex optimization is studied. Usually in convex optimization the minimization is over a d-dimensional domain. Very often the convergence rate of an optimization algorithm depends on the dimension d. The algorithms studied in this paper utilize dictionaries instead of a canonical basis used in the coordinate descent algorithms. We show how this approach allows us to reduce dimensionality of the problem. Also, we investigate which properties of a dictionary are beneficial for t...

MetHumi - Humidity Device for Mars MetNet Lander

Science.gov (United States)

Genzer, Maria; Polkko, Jouni; Harri, Ari-Matti; Schmidt, Walter; Leinonen, Jussi; Mäkinen, Teemu; Haukka, Harri

2010-05-01

MetNet Mars Mission focused for Martian atmospheric science is based on a new semihard landing vehicle called the MetNet Lander (MNL). The MNL will have a versatile science payload focused on the atmospheric science of Mars. The scientific payload of the MetNet Mission encompasses separate instrument packages for the atmospheric entry and descent phase and for the surface operation phase. MetHumi is the humidity sensor of MetNet Lander designed to work on Martian surface. It is based on Humicap® technology developed by Vaisala, Inc. MetHumi is a capacitive type of sensing device where an active polymer film changes capacitance as function of relative humidity. One MetHumi device package consists of one humidity transducer including three Humicap® sensor heads, an accurate temperature sensor head (Thermocap® by Vaisala, Inc.) and constant reference channels. MetHumi is very small, lightweighed and has low power consumption. It weighs only about 15 g without wires, and consumes 15 mW of power. MetHumi can make meaningful relative humidity measurements in range of 0 - 100%RH down to -70°C ambient temperature, but it survives even -135°C ambient temperature.

100 New Impact Crater Sites Found on Mars

Science.gov (United States)

Kennedy, M. R.; Malin, M. C.

2009-12-01

Recent observations constrain the formation of 100 new impact sites on Mars over the past decade; 19 of these were found using the Mars Global Surveyor Mars Orbiter Camera (MOC), and the other 81 have been identified since 2006 using the Mars Reconnaissance Orbiter Context Camera (CTX). Every 6 meter/pixel CTX image is examined upon receipt and, where they overlap images of 0.3-240 m/pixel scale acquired by the same or other Mars-orbiting spacecraft, we look for features that may have changed. New impact sites are initially identified by the presence of a new dark spot or cluster of dark spots in a CTX image. Such spots may be new impact craters, or result from the effect of impact blasts on the dusty surface. In some (generally rare) cases, the crater is sufficiently large to be resolved in the CTX image. In most cases, however, the crater(s) cannot be seen. These are tentatively designated as “candidate” new impact sites, and the CTX team then creates an opportunity for the MRO spacecraft to point its cameras off-nadir and requests that the High Resolution Imaging Science Experiment (HiRISE) team obtain an image of ~0.3 m/pixel to confirm whether a crater or crater cluster is present. It is clear even from cursory examination that the CTX observations are areographically biased to dusty, higher albedo areas on Mars. All but 3 of the 100 new impact sites occur on surfaces with Lambert albedo values in excess of 23.5%. Our initial study of MOC images greatly benefited from the initial global observations made in one month in 1999, creating a baseline date from which we could start counting new craters. The global coverage by MRO Mars Color Imager is more than a factor of 4 poorer in resolution than the MOC Wide Angle camera and does not offer the opportunity for global analysis. Instead, we must rely on partial global coverage and global coverage that has taken years to accumulate; thus we can only treat impact rates statistically. We subdivide the total data

Additive genetic variation in schizophrenia risk is shared by populations of African and European descent

NARCIS (Netherlands)

De Candia, T.r.; Lee, S.H.; Yang, J.; Browning, B.L.; Gejman, P. V.; Levinson, D. F.; Mowry, B. J.; Hewitt, J.K.; Goddard, M.E.; O'Donovan, M.C.; Purcell, S.M.; Posthuma, D.; Visscher, P. M.; Wray, N.R.; Keller, M. C.

2013-01-01

To investigate the extent to which the proportion of schizophrenia's additive genetic variation tagged by SNPs is shared by populations of European and African descent, we analyzed the largest combined African descent (AD [n = 2,142]) and European descent (ED [n = 4,990]) schizophrenia case-control

Network science landers for Mars

DEFF Research Database (Denmark)

Harri, A.M.; Marsal, O.; Lognonne, P.

1999-01-01

by the Mars Express Orbiter that is expected to be functional during the NetLander Mission's operational phase. Communication between the landers and the Earth would take place via a data relay onboard the Mars Express Orbiter. (C) 1999 COSPAR. Published by Elsevier Science Ltd.......The NetLander Mission will deploy four landers to the Martian surface. Each lander includes a network science payload with instrumentation for studying the interior of Mars, the atmosphere and the subsurface, as well as the ionospheric structure and geodesy. The NetLander Mission is the first......, ionospheric, geodetic measurements and ground penetrating radar mapping supported by panoramic images. The payloads also include entry phase measurements of the atmospheric vertical structure. The scientific data could be combined with simultaneous observations of the atmosphere and surface of Mars...

Topomapping of Mars with HRSC images, ISIS, and a commercial stereo workstation

Science.gov (United States)

Kirk, R. L.; Howington-Kraus, E.; Galuszka, D.; Redding, B.; Hare, T. M.

HRSC on Mars Express [1] is the first camera designed specifically for stereo imaging to be used in mapping a planet other than the Earth. Nine detectors view the planet through a single lens to obtain four-band color coverage and stereo images at 3 to 5 distinct angles in a single pass over the target. The short interval between acquisition of the images ensures that changes that could interfere with stereo matching are minimized. The resolution of the nadir channel is 12.5 m at periapsis, poorer at higher points in the elliptical orbit. The stereo channels are typically operated at 2x coarser resolution and the color channels at 4x or 8x. Since the commencement of operations in January 2004, approximately 58% of Mars has been imaged at nadir resolutions better than 50 m/pixel. This coverage is expected to increase significantly during the recently approved extended mission of Mars Express, giving the HRSC dataset enormous potential for regional and even global mapping. Systematic processing of the HRSC images is carried out at the German Aerospace Center (DLR) in Berlin. Preliminary digital topographic models (DTMs) at 200 m/post resolution and orthorectified image products are produced in near-realtime for all orbits, by using the VICAR software system [2]. The tradeoff of universal coverage but limited DTM resolution makes these products optimal for many but not all research studies. Experiments on adaptive processing with the same software, for a limited number of orbits, have allowed DTMs of higher resolution (down to 50 m/post) to be produced [3]. In addition, numerous Co-Investigators on the HRSC team (including ourselves) are actively researching techniques to improve on the standard products, by such methods as bundle adjustment, alternate approaches to stereo DTM generation, and refinement of DTMs by photoclinometry (shape-from-shading) [4]. The HRSC team is conducting a systematic comparison of these alternative processing approaches by arranging for

Analysis of foot clearance in firefighters during ascent and descent of stairs.

Science.gov (United States)

Kesler, Richard M; Horn, Gavin P; Rosengren, Karl S; Hsiao-Wecksler, Elizabeth T

2016-01-01

Slips, trips, and falls are a leading cause of injury to firefighters with many injuries occurring while traversing stairs, possibly exaggerated by acute fatigue from firefighting activities and/or asymmetric load carriage. This study examined the effects that fatigue, induced by simulated firefighting activities, and hose load carriage have on foot clearance while traversing stairs. Landing and passing foot clearances for each stair during ascent and descent of a short staircase were investigated. Clearances decreased significantly (p < 0.05) post-exercise for nine of 12 ascent parameters and increased for two of eight descent parameters. Load carriage resulted in significantly decreased (p < 0.05) clearance over three ascent parameters, and one increase during descent. Decreased clearances during ascent caused by fatigue or load carriage may result in an increased trip risk. Increased clearances during descent may suggest use of a compensation strategy to ensure stair clearance or an increased risk of over-stepping during descent. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Determination of accelerated factors in gradient descent iterations based on Taylor's series

Directory of Open Access Journals (Sweden)

Petrović Milena

2017-01-01

Full Text Available In this paper the efficiency of accelerated gradient descent methods regarding the way of determination of accelerated factor is considered. Due to the previous researches we assert that the use of Taylor's series of posed gradient descent iteration in calculation of accelerated parameter gives better final results than some other choices. We give a comparative analysis of efficiency of several methods with different approaches in obtaining accelerated parameter. According to the achieved results of numerical experiments we make a conclusion about the one of the most optimal way in defining accelerated parameter in accelerated gradient descent schemes.

Landscapes of Mars A Visual Tour

CERN Document Server

Vogt, Gregory L

2008-01-01

Landscapes of Mars is essentially a picture book that provides a visual tour of Mars. All the major regions and topographical features will be shown and supplemented with chapter introductions and extended captions. In a way, think of it as a visual tourist guide. Other topics covered are Martian uplands on the order of the elevation of Mt. Everest, Giant volcanoes and a rift system, the Grand Canyon of Mars, craters and the absence of craters over large regions (erosion), and wind shadows around craters, sand dunes, and dust devils. The book includes discussions on the search for water (braided channels, seepage, sedimentary layering, etc.) as well as on the Viking mission search for life, Mars meteorite fossil bacteria controversy, and planetary protection in future missions. The book concludes with an exciting gallery of the best 3D images of Mars making the book a perfect tool for understanding Mars and its place in the solar system.

Steepest descent approximations for accretive operator equations

International Nuclear Information System (INIS)

Chidume, C.E.

1993-03-01

A necessary and sufficient condition is established for the strong convergence of the steepest descent approximation to a solution of equations involving quasi-accretive operators defined on a uniformly smooth Banach space. (author). 49 refs

Solar radiation on Mars: Update 1991

Science.gov (United States)

Appelbaum, Joseph; Landis, Geoffrey A.

1991-01-01

Detailed information on solar radiation characteristics on Mars are necessary for effective design of future planned solar energy systems operating on the surface of Mars. A procedure and solar radiation related data are presented from which the daily variation of the global, direct beam and diffuse insolation on Mars are calculated. Given the optical depth of the Mars atmosphere, the global radiation is calculated from the normalized net flux function based on multiple wavelength and multiple scattering of the solar radiation. The direct beam was derived from the optical depth using Beer's law, and the diffuse component was obtained from the difference of the global and the direct beam radiation. The optical depths of the Mars atmosphere were derived from images taken of the Sun with a special diode on the cameras used on the two Viking Landers.

MOC's Highest Resolution View of Mars Pathfinder Landing Site

Science.gov (United States)

2000-01-01

[figure removed for brevity, see original site] (A) Mars Pathfinder site, left: April 1998; right: January 2000. [figure removed for brevity, see original site] (B) top: April 1998; bottom: January 2000.Can Mars Global Surveyor's 1.5 meter (5 ft) per pixel camera be used to find any evidence as to the fate of the Mars Polar Lander that was lost on December 3, 1999? One way to find out is to look for one of the other Mars landers and determine what, if anything, can be seen. There have been three successful Mars lander missions: Viking 1 (July 1976), Viking 2 (September 1976), and Mars Pathfinder (July 1997). Of these, the location of Mars Pathfinder is known the best because there are several distinct landmarks visible in the lander's images that help in locating the spacecraft. The MGS MOC Operations Team at Malin Space Science Systems has been tasked since mid-December 1999 with looking for the lost Polar Lander. Part of this effort has been to test the capabilities of MOC by taking a picture of the landing site of Mars Pathfinder.An attempt to photograph the Pathfinder site was made once before, in April 1998, by turning the entire MGS spacecraft so that the camera could point at the known location of the Mars Pathfinder lander. Turning the MGS spacecraft like this is not a normal operation--it takes considerable planning, and disrupts the on-going, normal acquisition of science data. It took 3 attempts to succeed, but on April 22, 1998, MOC acquired the picture seen on the left side of Figure A, above. The three near-by major landmarks that were visible to the Pathfinder's cameras are labeled here (North Peak, Big Crater, Twin Peaks). It was known at the time that this image was not adequate to see the Pathfinder lander because the camera was not in focus and had a resolution of only 3.3 meters (11 ft) per pixel. In this and all other images shown here, north is up. All views of the 1998 MOC image are illuminated from the lower right, all views of the 2000 MOC

Mars Science Laboratory Mission and Science Investigation

Science.gov (United States)

Grotzinger, John P.; Crisp, Joy; Vasavada, Ashwin R.; Anderson, Robert C.; Baker, Charles J.; Barry, Robert; Blake, David F.; Conrad, Pamela; Edgett, Kenneth S.; Ferdowski, Bobak; Gellert, Ralf; Gilbert, John B.; Golombek, Matt; Gómez-Elvira, Javier; Hassler, Donald M.; Jandura, Louise; Litvak, Maxim; Mahaffy, Paul; Maki, Justin; Meyer, Michael; Malin, Michael C.; Mitrofanov, Igor; Simmonds, John J.; Vaniman, David; Welch, Richard V.; Wiens, Roger C.

2012-09-01

-bearing strata, separated by an unconformity from overlying likely anhydrous strata; the landing ellipse is characterized by a mixture of alluvial fan and high thermal inertia/high albedo stratified deposits; and a number of stratigraphically/geomorphically distinct fluvial features. Samples of the crater wall and rim rock, and more recent to currently active surface materials also may be studied. Gale has a well-defined regional context and strong evidence for a progression through multiple potentially habitable environments. These environments are represented by a stratigraphic record of extraordinary extent, and insure preservation of a rich record of the environmental history of early Mars. The interior mountain of Gale Crater has been informally designated at Mount Sharp, in honor of the pioneering planetary scientist Robert Sharp. The major subsystems of the MSL Project consist of a single rover (with science payload), a Multi-Mission Radioisotope Thermoelectric Generator, an Earth-Mars cruise stage, an entry, descent, and landing system, a launch vehicle, and the mission operations and ground data systems. The primary communication path for downlink is relay through the Mars Reconnaissance Orbiter. The primary path for uplink to the rover is Direct-from-Earth. The secondary paths for downlink are Direct-to-Earth and relay through the Mars Odyssey orbiter. Curiosity is a scaled version of the 6-wheel drive, 4-wheel steering, rocker bogie system from the Mars Exploration Rovers (MER) Spirit and Opportunity and the Mars Pathfinder Sojourner. Like Spirit and Opportunity, Curiosity offers three primary modes of navigation: blind-drive, visual odometry, and visual odometry with hazard avoidance. Creation of terrain maps based on HiRISE (High Resolution Imaging Science Experiment) and other remote sensing data were used to conduct simulated driving with Curiosity in these various modes, and allowed selection of the Gale crater landing site which requires climbing the base of a

Ground reaction forces and frictional demands during stair descent: effects of age and illumination.

Science.gov (United States)

Christina, Kathryn A; Cavanagh, Peter R

2002-04-01

Stair descent is an inherently risky and demanding task that older adults often encounter in everyday life. It is believed that slip between the foot or shoe sole and the stair surface may play a role in stair related falls, however, there are no reports on slip resistance requirements for stair descent. The aim of this study was to determine the required coefficient of friction (RCOF) necessary for safe stair descent in 12 young and 12 older adults, under varied illuminance conditions. The RCOF during stair descent was found to be comparable in magnitude and time to that for overground walking, and thus, with adequate footwear and dry stair surfaces, friction does not appear to be a major determinant of stair safety. Illuminance level had little effect on the dependent variables quantified in this study. However, the older participants demonstrated safer strategies than the young during stair descent, as reflected by differences in the ground reaction forces and lower RCOF.

La construcción de la imagen de la ciudad. Mar del Plata y la apropiación del espacio frente al mar La construction de l'image de la ville. Mar del Plata et l'appropriation de l'espace face à la mer The construction of the city image. Mar del Plata and the appropriation of the space facing the sea

Directory of Open Access Journals (Sweden)

Graciela Iris Zuppa

2011-08-01

Full Text Available Cette étude propose une lecture interprétative de l’histoire urbaine et culturelle de Mar del Plata, un territoire dont le paysage côtier a connu d’importances modifications. Dans ce contexte de transformation, l’article étudie les pratiques publicitaires qui contribuent à la compréhension des caractéristiques de cet endroit, dans le but de proposer des interprétations autour des changements dans la construction de l’image de la ville, les représentations sociales qui les supportent,  les codes visuels et discursifs utilisés pour les transmettre.Pour atteindre ces objectifs, l’auteur analyse les émetteurs de messages, les images et les textes qui les accompagnent, le lien entre les deux instances, et l’interprétation qui émane d’elles. La récupération et la lecture interprétative de pièces graphiques, élaborées pour promouvoir la ville, permettent d’identifier et d’interpréter les caractéristiques fondamentales de la transition d’une station balnéaire élitiste qui devient une station qui se popularise. Par conséquent, l’étude des images successives de Mar del Plata entre 1930 et 1945 permet de suivre l’évolution de la station à travers les différentes campagnes definies par les politiques touristiques du gouvernement et les entreprises privées.This work proposes an interpretative reading of the urban and cultural history of Mar del Plata, a territory whose coastal scenery has been modified in a very important way. Once in this transformational context, we will analyse the advertising practices that contribute to understand the characteristics of the area, in order to offer an interpretation of the changes undergone in the construction of the city image, the social representations that support them and the visual and discursive codes used to transmit them.In order to achieve those aims, we are going to analyse the producers of those messages, the images and the written texts that are included

Inflammatory bowel disease in children of middle eastern descent.

Science.gov (United States)

Naidoo, Christina Mai Ying; Leach, Steven T; Day, Andrew S; Lemberg, Daniel A

2014-01-01

Increasing rates of inflammatory bowel disease (IBD) are now seen in populations where it was once uncommon. The pattern of IBD in children of Middle Eastern descent in Australia has never been reported. This study aimed to investigate the burden of IBD in children of Middle Eastern descent at the Sydney Children's Hospital, Randwick (SCHR). The SCHR IBD database was used to identify patients of self-reported Middle Eastern ethnicity diagnosed between 1987 and 2011. Demographic, diagnosis, and management data was collected for all Middle Eastern children and an age and gender matched non-Middle Eastern IBD control group. Twenty-four patients of Middle Eastern descent were identified. Middle Eastern Crohn's disease patients had higher disease activity at diagnosis, higher use of thiopurines, and less restricted colonic disease than controls. Although there were limitations with this dataset, we estimated a higher prevalence of IBD in Middle Eastern children and they had a different disease phenotype and behavior compared to the control group, with less disease restricted to the colon and likely a more active disease course.

Environmental effects on hormonal regulation of testicular descent

DEFF Research Database (Denmark)

Toppari, J; Virtanen, H E; Skakkebaek, N E

2006-01-01

cause some cases of undescended testis. Similarly, androgen insensitivity or androgen deficiency can cause cryptorchidism. Estrogens have been shown to down regulate INSL3 and thereby cause maldescent. Thus, a reduced androgen-estrogen ratio may disturb testicular descent. Environmental effects changing......Regulation of testicular descent is hormonally regulated, but the reasons for maldescent remain unknown in most cases. The main regulatory hormones are Leydig cell-derived testosterone and insulin-like factor 3 (INSL3). Luteinizing hormone (LH) stimulates the secretion of these hormones...... hypothesize that an exposure to a mixture of chemicals with anti-androgenic or estrogenic properties (either their own activity or their effect on androgen-estrogen ratio) may be involved in cryptorchidism....

Correlating multispectral imaging and compositional data from the Mars Exploration Rovers and implications for Mars Science Laboratory

Science.gov (United States)

Anderson, Ryan B.; Bell, James F.

2013-03-01

In an effort to infer compositional information about distant targets based on multispectral imaging data, we investigated methods of relating Mars Exploration Rover (MER) Pancam multispectral remote sensing observations to in situ alpha particle X-ray spectrometer (APXS)-derived elemental abundances and Mössbauer (MB)-derived abundances of Fe-bearing phases at the MER field sites in Gusev crater and Meridiani Planum. The majority of the partial correlation coefficients between these data sets were not statistically significant. Restricting the targets to those that were abraded by the rock abrasion tool (RAT) led to improved Pearson’s correlations, most notably between the red-blue ratio (673 nm/434 nm) and Fe3+-bearing phases, but partial correlations were not statistically significant. Partial Least Squares (PLS) calculations relating Pancam 11-color visible to near-IR (VNIR; ∼400-1000 nm) “spectra” to APXS and Mössbauer element or mineral abundances showed generally poor performance, although the presence of compositional outliers led to improved PLS results for data from Meridiani. When the Meridiani PLS model for pyroxene was tested by predicting the pyroxene content of Gusev targets, the results were poor, indicating that the PLS models for Meridiani are not applicable to data from other sites. Soft Independent Modeling of Class Analogy (SIMCA) classification of Gusev crater data showed mixed results. Of the 24 Gusev test regions of interest (ROIs) with known classes, 11 had >30% of the pixels in the ROI classified correctly, while others were mis-classified or unclassified. k-Means clustering of APXS and Mössbauer data was used to assign Meridiani targets to compositional classes. The clustering-derived classes corresponded to meaningful geologic and/or color unit differences, and SIMCA classification using these classes was somewhat successful, with >30% of pixels correctly classified in 9 of the 11 ROIs with known classes. This work shows that

The stratigraphy of Mars

Science.gov (United States)

Tanaka, Kenneth L.

1986-01-01

A global stratigraphy of Mars was developed from a global geologic map series derived from Viking images; the stratigraphy is composed of three maps. A new chronostratigraphic classification system which consists of lower, middle, and upper Noachian, Hesperian, and Amazonian systems is described. The crater-density boundaries of the chronostratigraphic units and the absolute ages of the Martian epochs aer estimated. The relative ages of major geologic units and featues are calculated and analyzed. The geologic history of Mars is summarized on the maps in terms of epochs.

Changes in labial capillary density on ascent to and descent from high altitude [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Edward Gilbert-Kawai

2016-08-01

Full Text Available Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site.  Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021. There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017. Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area, despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains

The iMars WebGIS - A Central Hub for Displaying and Distributing Co-Registered Data of Mars

Science.gov (United States)

van Gasselt, S.; Morley, J.; Houghton, R.; Bamford, S.; Ivanov, A.; Muller, J.-P.; Yershov, V.; Sidiripoulos, P.; Gwinner, K.; Waehlisch, M.; Kim, J. R.

2014-04-01

The iMars-project [1] is an EU funded R&D project which has started in 2014 and which is aimed at developing an automated processing system for generating image stacks of high-precision, co-registered, terrain-corrected and multi-temporal data of Mars obtained since 1977. It is anticipated that the entire NASA and ESA record of orbital image data will be co-registered and terrain-corrected in 2015 [1] so that time-series data can be generated for subsequent analyses. Such analyses will be conducted automatically using change-detection algorithms or interactively and visually using the citizen-science concept implemented at Zooniverse [2]. For more detailed information see [1] and visit the project's website at http://www.i-Mars.eu. Close user interaction plays a paramount role within iMars which requires sophisticated concepts for data handling and communication allowing users to integrate, analyse and visualise data from a central location. This interactive data hub will be realised through open-source webGIS implementations and by providing webGIS services to the user community using established OGC-protocols (see Fig. 1, [3, 4, 5]).

Multidisciplinary Tool for Systems Analysis of Planetary Entry, Descent, and Landing

Science.gov (United States)

Samareh, Jamshid A.

2011-01-01

Systems analysis of a planetary entry (SAPE), descent, and landing (EDL) is a multidisciplinary activity in nature. SAPE improves the performance of the systems analysis team by automating and streamlining the process, and this improvement can reduce the errors that stem from manual data transfer among discipline experts. SAPE is a multidisciplinary tool for systems analysis of planetary EDL for Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Titan. It performs EDL systems analysis for any planet, operates cross-platform (i.e., Windows, Mac, and Linux operating systems), uses existing software components and open-source software to avoid software licensing issues, performs low-fidelity systems analysis in one hour on a computer that is comparable to an average laptop, and keeps discipline experts in the analysis loop. SAPE uses Python, a platform-independent, open-source language, for integration and for the user interface. Development has relied heavily on the object-oriented programming capabilities that are available in Python. Modules are provided to interface with commercial and government off-the-shelf software components (e.g., thermal protection systems and finite-element analysis). SAPE currently includes the following analysis modules: geometry, trajectory, aerodynamics, aerothermal, thermal protection system, and interface for structural sizing.

Whole-body angular momentum during stair ascent and descent.

Science.gov (United States)

Silverman, Anne K; Neptune, Richard R; Sinitski, Emily H; Wilken, Jason M

2014-04-01

The generation of whole-body angular momentum is essential in many locomotor tasks and must be regulated in order to maintain dynamic balance. However, angular momentum has not been investigated during stair walking, which is an activity that presents a biomechanical challenge for balance-impaired populations. We investigated three-dimensional whole-body angular momentum during stair ascent and descent and compared it to level walking. Three-dimensional body-segment kinematic and ground reaction force (GRF) data were collected from 30 healthy subjects. Angular momentum was calculated using a 13-segment whole-body model. GRFs, external moment arms and net joint moments were used to interpret the angular momentum results. The range of frontal plane angular momentum was greater for stair ascent relative to level walking. In the transverse and sagittal planes, the range of angular momentum was smaller in stair ascent and descent relative to level walking. Significant differences were also found in the ground reaction forces, external moment arms and net joint moments. The sagittal plane angular momentum results suggest that individuals alter angular momentum to effectively counteract potential trips during stair ascent, and reduce the range of angular momentum to avoid falling forward during stair descent. Further, significant differences in joint moments suggest potential neuromuscular mechanisms that account for the differences in angular momentum between walking conditions. These results provide a baseline for comparison to impaired populations that have difficulty maintaining dynamic balance, particularly during stair ascent and descent. Copyright © 2014 Elsevier B.V. All rights reserved.

Solar radiation for Mars power systems

Science.gov (United States)

Appelbaum, Joseph; Landis, Geoffrey A.

1991-01-01

Detailed information about the solar radiation characteristics on Mars are necessary for effective design of future planned solar energy systems operating on the surface of Mars. A procedure and solar radiation related data from which the diurnally and daily variation of the global, direct (or beam), and diffuse insolation on Mars are calculated, are presented. The radiation data are based on measured optical depth of the Martian atmosphere derived from images taken of the Sun with a special diode on the Viking Lander cameras; and computation based on multiple wavelength and multiple scattering of the solar radiation.

Artificial structures on Mars

Science.gov (United States)

Van Flandern, T.

2002-05-01

Approximately 70,000 images of the surface of Mars at a resolution of up to 1.4 meters per pixel, taken by the Mars Global Surveyor spacecraft, are now in public archives. Approximately 1% of those images show features that can be broadly described as `special shapes', `tracks, trails, and possible vegetation', `spots, stripes, and tubes', `artistic imagery', and `patterns and symbols'. Rather than optical illusions and tricks of light and shadow, most of these have the character that, if photographed on Earth, no one would doubt that they were the products of large biology and intelligence. In a few cases, relationships, context, and fulfillment of a priori predictions provide objective evidence of artificiality that is exempt from the influence of experimenter biases. Only controlled test results can be trusted because biases are strong and operate both for and against artificiality.

The Global and Local Characters of Mars Perihelion Cloud Trails

Science.gov (United States)

Clancy, R. T.; Wolff, M. J.; Smith, M. D.; Cantor, B. A.; Spiga, A.

2014-12-01

We present the seasonal and spatial distribution of Mars perihelion cloud trails as mapped from Mars Reconnaissance Orbiter (MRO) MARCI (Mars Color Imager) imaging observations in 2 ultraviolet and 3 visible filters. The extended 2007-2013 period of MARCI daily global image maps reveals the widespread distribution of these high altitude clouds, which are somewhat paradoxically associated with specific surface regions. They appear as longitudinally extended (300-700 km) cloud trails with distinct leading plumes of substantial ice cloud optical depths (0.02-0.2) for such high altitudes of occurrence (40-50 km, from cloud surface shadow measurements). These plumes generate small ice particles (Reff~1 to reflect locally elevated mesospheric water ice formation that may impact the global expression of mesospheric water ice aerosols.

Descent construction for GSpin groups

CERN Document Server

Hundley, Joseph

2016-01-01

In this paper the authors provide an extension of the theory of descent of Ginzburg-Rallis-Soudry to the context of essentially self-dual representations, that is, representations which are isomorphic to the twist of their own contragredient by some Hecke character. The authors' theory supplements the recent work of Asgari-Shahidi on the functorial lift from (split and quasisplit forms of) GSpin_{2n} to GL_{2n}.

Small Spacecraft Constellation Concept for Mars Atmospheric Radio Occultations

Science.gov (United States)

Asmar, S. W.; Mannucci, A. J.; Ao, C. O.; Kobayashi, M. M.; Lazio, J.; Marinan, A.; Massone, G.; McCandless, S. E.; Preston, R. A.; Seubert, J.; Williamson, W.

2017-12-01

First demonstrated in 1965 when Mariner IV flew by Mars and determined the salient features of its atmosphere, radio occultation experiments have been carried out on numerous planetary missions with great discoveries. These experiments utilize the now classic configuration of a signal from a single planetary spacecraft to Earth receiving stations, where the science data are acquired. The Earth science community advanced the technique to utilizing a constellation of spacecraft with the radio occultation links between the spacecraft, enabled by the infrastructure of the Global Positioning System. With the advent of small and less costly spacecraft, such as planetary CubeSats and other variations, such as the anticipated innovative Mars Cube One mission, crosslinks among small spacecraft can be used to study other planets in the near future. Advantages of this type of experiment include significantly greater geographical coverage, which could reach global coverage over a few weeks with a small number of spacecraft. Repeatability of the global coverage can lead to examining temperature-pressure profiles and ionospheric electron density profiles, on daily, seasonal, annual, or other time scales of interest. The higher signal-to-noise ratio for inter-satellite links, compared to a link to Earth, decreases the design demands on the instrumentation (smaller antennas and transmitters, etc.). After an actual Mars crosslink demonstration, this concept has been in development using Mars as a possible target. Scientific objectives, delivery methods, operational scenarios and end-to-end configuration have been documented. Science objectives include determining the state and variability of the lower Martian atmosphere, which has been an identified as a high priority objective by the Mars Exploration Program Analysis Group, particularly as it relates to entry, descent, and landing and ascent for future crewed and robotic missions. This paper will present the latest research on the

Spiders from Mars?

Science.gov (United States)

2003-01-01

MGS MOC Release No. MOC2-426, 19 July 2003No, this is not a picture of a giant, martian spider web. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a plethora of polygonal features on the floor of a northern hemisphere impact crater near 65.6oN, 327.7oW. The picture was acquired during spring, after the seasonal carbon dioxide frost cap had largely migrated through the region. At the time the picture was taken, remnants of seasonal frost remained on the crater rim and on the edges of the troughs that bound each of the polygons. Frost often provides a helpful hint as to where polygons and patterned ground occur. The polygons, if they were on Earth, would indicate the presence of freeze-thaw cycles in ground ice. Although uncertain, the same might be true of Mars. Sunlight illuminates the scene from the lower left.

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.

The New Mars Synthesis: A New Concept Of Mars Geo-Chemical History

Science.gov (United States)

Brandenburg, J. E.

2005-02-01

A new concept of Mars climatic and geo-chemical evolution is proposed, called the NMS (New Mars Synthesis) drawing on the full spectrum of available Mars data. The proposed synthesis is that Mars and Earth, having begun with similar surface conditions, did not strongly diverge from their similar paths 4.0 Billion years ago, in the Early Noachian, instead, under the NMS, they diverged much more recently in geologic time, in the Early Amazonian. Under the NMS, biology strongly affected the geo-chemical evolution of Mars, and allowed a stable and persistent greenhouse by producing a large oxygen component in the atmosphere. The NMS assumes Mars held biology form early on, has been geologically active throughout its history, that it had a northern paleo-ocean, that it has high, approximately, 4xLunar, cratering rates and that its climate changed recently in geologic time from being basically terrestrial to its present conditions. The proposed mechanism for the stability of the Mars greenhouse was a large oxygen component in the atmosphere that created acidic and highly oxidized conditions that prevented formation of Carbonates, and the thermal and gas buffering of the paleo-ocean. The greenhouse was thus biologically and hydrologically stabilized. The greenhouse was terminated by a large atmospheric cooling event in the Early Amazonian that killed the biosphere and froze the ocean stabilizing the greenhouse. This cooling event was probably caused by the formation of the Lyot impact basin. Given the long duration of this terrestrial biosphere in this NMS, the possible appearance of fossils in some rover images is not to be unexpected and the colonization of Mars by humanity may be aided extensive fossil biomass to use as raw material.

Mars At Opposition

Science.gov (United States)

1995-01-01

These NASA Hubble Space Telescope views provide the most detailed complete global coverage of the red planet Mars ever seen from Earth. The pictures were taken on February 25, 1995, when Mars was at a distance of 65 million miles (103 million km).To the surprise of researchers, Mars is cloudier than seen in previous years. This means the planet is cooler and drier, because water vapor in the atmosphere freezes out to form ice-crystal clouds. Hubble resolves Martian surface features with a level of detail only exceeded by planetary probes, such as impact craters and other features as small as 30 miles (50 kilometers) across.[Tharsis region] - A crescent-shaped cloud just right of center identifies the immense shield volcano Olympus Mons, which is 340 miles (550 km) across at its base. Warm afternoon air pushed up over the summit forms ice-crystal clouds downwind from the volcano. Farther to the east (right) a line of clouds forms over a row of three extinct volcanoes which are from north to south: Ascraeus Mons, Pavonis Mons, Arsia Mons. It's part of an unusual, recurring 'W'-shaped cloud formation that once mystified earlier ground-based observers.[Valles Marineris region] - The 16 mile-high volcano Ascraeus Mons pokes through the cloud deck along the western (left) limb of the planet. Other interesting geologic features include (lower left) Valles Marineris, an immense rift valley the length of the continental United States. Near the image center lies the Chryse basin made up of cratered and chaotic terrain. The oval-looking Argyre impact basin (bottom) appears white due to clouds or frost.[Syrtis Major region] - The dark 'shark fin' feature left of center is Syrtis Major. Below it the giant impact basin Hellas. Clouds cover several great volcanos in the Elysium region near the eastern (right) limb. As clearly seen in the Hubble images, past dust storms in Mars' southern hemisphere have scoured the plains of fine light dust and transported the dust northward. This

Convective descent simulations of drilling discharges on Georges and Sable Island banks

International Nuclear Information System (INIS)

Andrade, Y.; Loder, J.W.

1997-01-01

Factors affecting the fate of drilling mud discharges on Georges and Sable Island Banks were examined. The Koh and Chang jet discharge model was used to simulate the convective descent of a jet discharge of relatively dense materials at sites representing different hydrographic and depth regimes with a range of mud densities, and different discharge configurations, ocean currents and seasonal stratifications. The study revealed the dependence of the depth of descent and properties of the discharge plume on the discharge configuration and oceanographic conditions. The factors that affected the depth of descent were mud density, depth of release, initial downward volume flux of the discharge, current strength and ocean stratification. 22 refs., 3 tabs., 59 figs

SUV Tracks On Mars? The 'Devil' is in the Details

Science.gov (United States)

1998-01-01

Sport Utility Vehicles (SUVs) on Mars? Imagine the MOC imaging team's surprise on the morning of April 27, 1998, as the latest images came in from the 'Red Planet.'A picture taken by the camera on Mars Global Surveyor just one day earlier showed several thin, dark lines that--at first glance--looked like pathways blazed by off-road sport utility vehicles. Who's been driving around on Mars?The MOC image in question (#26403), seen here at full resolution of 13.8 meters (45 feet) per pixel, was obtained around 10:22 a.m. PDT on April 26, 1998, during Mars Global Surveyor's 264th orbit. North is approximately up, illumination is from the lower right. Located in eastern Arabia Terra near 16.5o N latitude, 311.4o W longitude, the image showed a number of natural features--small craters formed by meteor impact, several buttes and mesas left by erosion of the surrounding terrain, small dunes and drifts, and a mantle of dust that varies in thickness from place to place. But the new picture also showed two dark lines--each varying in width up to about 15 meters (49 feet)--that extended several kilometers/miles across the image.Lines like these have been seen before on Mars. They are most likely the result of dust devils--columnar vortices of wind that move across the landscape, pick up dust, and look somewhat like miniature tornadoes. Dust devils are a common occurrence in dry and desert landscapes on Earth as well as Mars. They form when the ground heats up during the day, warming the air immediately above the surface. As pockets of warm air rise and interfere with one another, they create horizontal pressure variations that, combined with other meteorological winds, cause the upward moving air to spin (the direction of the spin is controlled by the same Coriolis forces that cause terrestrial hurricanes to spin in specific directions). As the spinning column of air moves across the surface, it occasionally encounters dust on the surface, which it can suck upward. This dust

Charged particles radiation measurements with Liulin-MO dosimeter of FREND instrument aboard ExoMars Trace Gas Orbiter during the transit and in high elliptic Mars orbit

Science.gov (United States)

Semkova, Jordanka; Koleva, Rositza; Benghin, Victor; Dachev, Tsvetan; Matviichuk, Yuri; Tomov, Borislav; Krastev, Krasimir; Maltchev, Stephan; Dimitrov, Plamen; Mitrofanov, Igor; Malahov, Alexey; Golovin, Dmitry; Mokrousov, Maxim; Sanin, Anton; Litvak, Maxim; Kozyrev, Andrey; Tretyakov, Vladislav; Nikiforov, Sergey; Vostrukhin, Andrey; Fedosov, Fedor; Grebennikova, Natalia; Zelenyi, Lev; Shurshakov, Vyacheslav; Drobishev, Sergey

2018-03-01

ExoMars is a joint ESA-Rosscosmos program for investigating Mars. Two missions are foreseen within this program: one consisting of the Trace Gas Orbiter (TGO), that carries scientific instruments for the detection of trace gases in the Martian atmosphere and for the location of their source regions, plus an Entry, Descent and landing demonstrator Module (EDM), launched on March 14, 2016; and the other, featuring a rover and a surface platform, with a launch date of 2020. On October 19, 2016 TGO was inserted into high elliptic Mars' orbit. The dosimetric telescope Liulin-MO for measuring the radiation environment onboard the ExoMars 2016 TGO is a module of the Fine Resolution Epithermal Neutron Detector (FREND). Here we present first results from measurements of the charged particle fluxes, dose rates, Linear Energy Transfer (LET) spectra and estimation of dose equivalent rates in the interplanetary space during the cruise of TGO to Mars and first results from dosimetric measurements in high elliptic Mars' orbit. A comparison is made with the dose rates obtained by RAD instrument onboard Mars Science Laboratory during the cruise to Mars in 2011-2012 and with the Galactic Cosmic Rays (GCR) count rates provided by other particle detectors currently in space. The average measured dose rate in Si from GCR during the transit to Mars for the period April 22-September 15, 2016 is 372 ± 37 μGy d-1 and 390 ± 39 μGy d-1 in two perpendicular directions. The dose equivalent rate from GCR for the same time period is about 2 ± 0.3 mSv d-1. This is in good agreement with RAD results for radiation dose rate in Si from GCR in the interplanetary space, taking into account the different solar activity during the measurements of both instruments. About 10% increase of the dose rate, and 15% increase of the dose equivalent rate for 10.5 months flight is observed. It is due to the increase of Liulin-MO particle fluxes for that period and corresponds to the overall GCR intensity

A technician works on the Mars Climate Orbiter in SAEF-2

Science.gov (United States)

1998-01-01

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), a technician works on the Mars Climate Orbiter which is scheduled to launch on Dec. 10, 1998, aboard a Boeing Delta II rocket. The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface.

Conjugate descent formulation of backpropagation error in ...

African Journals Online (AJOL)

The feedforward neural network architecture uses backpropagation learning to determine optimal weights between dierent interconnected layers. This learning procedure uses a gradient descent technique applied to a sum-of-squares error function for the given input-output pattern. It employs an iterative procedure to ...

MetBaro - Pressure Instrument for Mars MetNet Lander

Science.gov (United States)

Polkko, J.; Haukka, H.; Harri, A.-M.; Schmidt, W.; Leinonen, J.; Mäkinen, T.

2009-04-01

THE METNET MISSION FOCUSED ON THE Martian atmospheric science is based on a new semihard landing vehicle called the MetNet Lander (MNL). The MNL will have a versatile science payload focused on the atmospheric science of Mars. The scientific payload of the MetNet Mission encompasses separate instrument packages for the atmospheric entry and descent phase and for the surface operation phase. MetBaro is the pressure instrument of MetNet Lander designed to work on Martian surface. It is based on Barocap® technology developed by Vaisala, Inc. MetBaro is a capacitic type of sensing device where capasitor plates are moved by ambient pressure. MetBaro device consists of two pressure transducers including a total of 6 Barocap® sensor heads of high-stability and high-resolution types. The long-term stability of MetBaro is in order of 20…50 µBar and resolution a few µBar. MetBaro is small, lightweighed and has low power consumption. It weighs about 50g without wires and controlling FPGA, and consumes 15 mW of power. A similar device has successfully flown in Phoenix mission, where it performed months of measurements on Martian ground. Another device is also part of the Mars Science Laboratory REMS instrument (to be launched in 2011).

Asymptotic Parachute Performance Sensitivity

Science.gov (United States)

Way, David W.; Powell, Richard W.; Chen, Allen; Steltzner, Adam D.

2006-01-01

In 2010, the Mars Science Laboratory mission will pioneer the next generation of robotic Entry, Descent, and Landing systems by delivering the largest and most capable rover to date to the surface of Mars. In addition to landing more mass than any other mission to Mars, Mars Science Laboratory will also provide scientists with unprecedented access to regions of Mars that have been previously unreachable. By providing an Entry, Descent, and Landing system capable of landing at altitudes as high as 2 km above the reference gravitational equipotential surface, or areoid, as defined by the Mars Orbiting Laser Altimeter program, Mars Science Laboratory will demonstrate sufficient performance to land on 83% of the planet s surface. By contrast, the highest altitude landing to date on Mars has been the Mars Exploration Rover at 1.3 km below the areoid. The coupling of this improved altitude performance with latitude limits as large as 60 degrees off of the equator and a precise delivery to within 10 km of a surface target, will allow the science community to select the Mars Science Laboratory landing site from thousands of scientifically interesting possibilities. In meeting these requirements, Mars Science Laboratory is extending the limits of the Entry, Descent, and Landing technologies qualified by the Mars Viking, Mars Pathfinder, and Mars Exploration Rover missions. Specifically, the drag deceleration provided by a Viking-heritage 16.15 m supersonic Disk-Gap-Band parachute in the thin atmosphere of Mars is insufficient, at the altitudes and ballistic coefficients under consideration by the Mars Science Laboratory project, to maintain necessary altitude performance and timeline margin. This paper defines and discusses the asymptotic parachute performance observed in Monte Carlo simulation and performance analysis and its effect on the Mars Science Laboratory Entry, Descent, and Landing architecture.

Immediate effects of a distal gait modification during stair descent in individuals with patellofemoral pain.

Science.gov (United States)

Aliberti, Sandra; Mezêncio, Bruno; Amadio, Alberto Carlos; Serrão, Julio Cerca; Mochizuki, Luis

2018-05-23

Knee pain during stair managing is a common complaint among individuals with PFP and can negatively affect their activities of daily living. Gait modification programs can be used to decrease patellofemoral pain. Immediate effects of a stair descent distal gait modification session that intended to emphasize forefoot landing during stair descent are described in this study. To analyze the immediate effects of a distal gait modification session on lower extremity movements and intensity of pain in women with patellofemoral pain during stair descent. Nonrandomized controlled trial. Sixteen women with patellofemoral pain were allocated into two groups: (1) Gait Modification Group (n = 8); and 2) Control Group (n = 8). The intensity of pain (visual analog scale) and kinematics of knee, ankle, and forefoot (multi-segmental foot model) during stair descent were assessed before and after the intervention. After the gait modification session, there was an increase of forefoot eversion and ankle plantarflexion as well as a decrease of knee flexion. An immediate decrease in patellofemoral pain intensity during stair descent was also observed. The distal gait modification session changed the lower extremity kinetic chain strategy of movement, increasing foot and ankle movement contribution and decreasing knee contribution to the task. An immediate decrease in patellofemoral pain intensity during stair descent was also observed. To emphasize forefoot landing may be a useful intervention to immediately relieve pain in patients with patellofemoral pain during stair descent. Clinical studies are needed to verify the gait modification session effects in medium and long terms.

Ascent, descent, nullity, defect, and related notions for linear relations in linear spaces

NARCIS (Netherlands)

Sandovici, Adrian; de Snoo, Henk; Winkler, Henrik

2007-01-01

For a linear relation in a linear space the concepts of ascent, descent, nullity, and defect are introduced and studied. It is shown that the results of A.E. Taylor and M.A. Kaashoek concerning the relationship between ascent, descent, nullity, and defect for the case of linear operators remain

Ionospheric forecasting model using fuzzy logic-based gradient descent method

Directory of Open Access Journals (Sweden)

D. Venkata Ratnam

2017-09-01

Full Text Available Space weather phenomena cause satellite to ground or satellite to aircraft transmission outages over the VHF to L-band frequency range, particularly in the low latitude region. Global Positioning System (GPS is primarily susceptible to this form of space weather. Faulty GPS signals are attributed to ionospheric error, which is a function of Total Electron Content (TEC. Importantly, precise forecasts of space weather conditions and appropriate hazard observant cautions required for ionospheric space weather observations are limited. In this paper, a fuzzy logic-based gradient descent method has been proposed to forecast the ionospheric TEC values. In this technique, membership functions have been tuned based on the gradient descent estimated values. The proposed algorithm has been tested with the TEC data of two geomagnetic storms in the low latitude station of KL University, Guntur, India (16.44°N, 80.62°E. It has been found that the gradient descent method performs well and the predicted TEC values are close to the original TEC measurements.

Testicular descent: INSL3, testosterone, genes and the intrauterine milieu.

Science.gov (United States)

Bay, Katrine; Main, Katharina M; Toppari, Jorma; Skakkebæk, Niels E

2011-04-01

Complete testicular descent is a sign of, and a prerequisite for, normal testicular function in adult life. The process of testis descent is dependent on gubernacular growth and reorganization, which is regulated by the Leydig cell hormones insulin-like peptide 3 (INSL3) and testosterone. Investigation of the role of INSL3 and its receptor, relaxin-family peptide receptor 2 (RXFP2), has contributed substantially to our understanding of the hormonal control of testicular descent. Cryptorchidism is a common congenital malformation, which is seen in 2-9% of newborn boys, and confers an increased risk of infertility and testicular cancer in adulthood. Although some cases of isolated cryptorchidism in humans can be ascribed to known genetic defects, such as mutations in INSL3 or RXFP2, the cause of cryptorchidism remains unknown in most patients. Several animal and human studies are currently underway to test the hypothesis that in utero factors, including environmental and maternal lifestyle factors, may be involved in the etiology of cryptorchidism. Overall, the etiology of isolated cryptorchidism seems to be complex and multifactorial, involving both genetic and nongenetic components.

The MARS Photon Processing Cameras for Spectral CT

CERN Document Server

Doesburg, Robert Michael Nicholas; Butler, APH; Renaud, PF

This thesis is about the development of the MARS camera: a stan- dalone portable digital x-ray camera with spectral sensitivity. It is built for use in the MARS Spectral system from the Medipix2 and Medipix3 imaging chips. Photon counting detectors and Spectral CT are introduced, and Medipix is identified as a powerful new imaging device. The goals and strategy for the MARS camera are discussed. The Medipix chip physical, electronic and functional aspects, and ex- perience gained, are described. The camera hardware, firmware and supporting PC software are presented. Reports of experimental work on the process of equalisation from noise, and of tests of charge sum- ming mode, conclude the main body of the thesis. The camera has been actively used since late 2009 in pre-clinical re- search. A list of publications that derive from the use of the camera and the MARS Spectral scanner demonstrates the practical benefits already obtained from this work. Two of the publications are first- author, eight are co-authore...

Impact of race on the professional lives of physicians of African descent.

Science.gov (United States)

Nunez-Smith, Marcella; Curry, Leslie A; Bigby, JudyAnn; Berg, David; Krumholz, Harlan M; Bradley, Elizabeth H

2007-01-02

Increasing the racial and ethnic diversity of the physician workforce is a national priority. However, insight into the professional experiences of minority physicians is limited. This knowledge is fundamental to developing effective strategies to recruit, retain, and support a diverse physician workforce. To characterize how physicians of African descent experience race in the workplace. Qualitative study based on in-person and in-depth racially concordant interviews using a standard discussion guide. The 6 New England states in the United States. 25 practicing physicians of African descent representing a diverse range of primary practice settings, specialties, and ages. Professional experiences of physicians of African descent. 1) Awareness of race permeates the experience of physicians of African descent in the health care workplace; 2) race-related experiences shape interpersonal interactions and define the institutional climate; 3) responses to perceived racism at work vary along a spectrum from minimization to confrontation; 4) the health care workplace is often silent on issues of race; and 5) collective race-related experiences can result in "racial fatigue," with personal and professional consequences for physicians. The study was restricted to New England and may not reflect the experiences of physicians in other geographic regions. The findings are meant to be hypothesis-generating and require additional follow-up studies. The issue of race remains a pervasive influence in the work lives of physicians of African descent. Without sufficient attention to the specific ways in which race shapes physicians' work experiences, health care organizations are unlikely to create environments that successfully foster and sustain a diverse physician workforce.

Counseling and Psychotherapy with Clients of Middle Eastern Descent: A Qualitative Inquiry

OpenAIRE

Boghosian, Sara

2011-01-01

It is becoming increasingly important for clinical and counseling psychologists to have multicultural competence skills for treating an increasingly diverse client population. The psychology literature related to culturally competent treatment with persons of Middle Eastern descent is currently limited. In this study, qualitative methodology was utilized to explore the mental health attitudes and psychotherapy experiences of clients of Middle Eastern descent. Participants described culturally...

Gradient descent learning algorithm overview: a general dynamical systems perspective.

Science.gov (United States)

Baldi, P

1995-01-01

Gives a unified treatment of gradient descent learning algorithms for neural networks using a general framework of dynamical systems. This general approach organizes and simplifies all the known algorithms and results which have been originally derived for different problems (fixed point/trajectory learning), for different models (discrete/continuous), for different architectures (forward/recurrent), and using different techniques (backpropagation, variational calculus, adjoint methods, etc.). The general approach can also be applied to derive new algorithms. The author then briefly examines some of the complexity issues and limitations intrinsic to gradient descent learning. Throughout the paper, the author focuses on the problem of trajectory learning.

Global Patterns of Prostate Cancer Incidence, Aggressiveness, and Mortality in Men of African Descent

Directory of Open Access Journals (Sweden)

Timothy R. Rebbeck

2013-01-01

Full Text Available Prostate cancer (CaP is the leading cancer among men of African descent in the USA, Caribbean, and Sub-Saharan Africa (SSA. The estimated number of CaP deaths in SSA during 2008 was more than five times that among African Americans and is expected to double in Africa by 2030. We summarize publicly available CaP data and collected data from the men of African descent and Carcinoma of the Prostate (MADCaP Consortium and the African Caribbean Cancer Consortium (AC3 to evaluate CaP incidence and mortality in men of African descent worldwide. CaP incidence and mortality are highest in men of African descent in the USA and the Caribbean. Tumor stage and grade were highest in SSA. We report a higher proportion of T1 stage prostate tumors in countries with greater percent gross domestic product spent on health care and physicians per 100,000 persons. We also observed that regions with a higher proportion of advanced tumors reported lower mortality rates. This finding suggests that CaP is underdiagnosed and/or underreported in SSA men. Nonetheless, CaP incidence and mortality represent a significant public health problem in men of African descent around the world.

EU-FP7-iMARS: Analysis of Mars Multi-Resolution Images Using Auto-Coregistration Data Mining and Crowd Source Techniques: Processed Results - a First Look

Science.gov (United States)

Muller, Jan-Peter; Tao, Yu; Sidiropoulos, Panagiotis; Gwinner, Klaus; Willner, Konrad; Fanara, Lida; Waehlisch, Marita; van Gasselt, Stephan; Walter, Sebastian; Steikert, Ralf; Schreiner, Bjoern; Ivanov, Anton; Cantini, Federico; Wardlaw, Jessica; Morley, Jeremy; Sprinks, James; Giordano, Michele; Marsh, Stuart; Kim, Jungrack; Houghton, Robert; Bamford, Steven

2016-06-01

Understanding planetary atmosphere-surface exchange and extra-terrestrial-surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 15 years, especially in 3D imaging of surface shape. This has led to the ability to overlay image data and derived information from different epochs, back in time to the mid 1970s, to examine changes through time, such as the recent discovery of mass movement, tracking inter-year seasonal changes and looking for occurrences of fresh craters. Within the EU FP-7 iMars project, we have developed a fully automated multi-resolution DTM processing chain, called the Coregistration ASP-Gotcha Optimised (CASP-GO), based on the open source NASA Ames Stereo Pipeline (ASP) [Tao et al., this conference], which is being applied to the production of planetwide DTMs and ORIs (OrthoRectified Images) from CTX and HiRISE. Alongside the production of individual strip CTX & HiRISE DTMs & ORIs, DLR [Gwinner et al., 2015] have processed HRSC mosaics of ORIs and DTMs for complete areas in a consistent manner using photogrammetric bundle block adjustment techniques. A novel automated co-registration and orthorectification chain has been developed by [Sidiropoulos & Muller, this conference]. Using the HRSC map products (both mosaics and orbital strips) as a map-base it is being applied to many of the 400,000 level-1 EDR images taken by the 4 NASA orbital cameras. In particular, the NASA Viking Orbiter camera (VO), Mars Orbiter Camera (MOC), Context Camera (CTX) as well as the High Resolution Imaging Science Experiment (HiRISE) back to 1976. A webGIS has been developed [van Gasselt et al., this conference] for displaying this time sequence of imagery and will be demonstrated showing an example from one of the HRSC quadrangle map-sheets. Automated quality control [Sidiropoulos & Muller, 2015] techniques are applied to screen for

Corrugated thimble tube for controlling control rod descent in nuclear reactor

International Nuclear Information System (INIS)

Luetzow, H.J.

1981-01-01

A thimble tube construction is described which will provide a controlled descent for a control rod while minimizing the reaction forces which must be absorbed by the thimble tube and reducing the possibility that a foreign particle could interfere with the free descent of a control rod. A thimble tube is formed with helically-corrugate internal walls which cooperate with a control rod contained in the tube in an emergency situation to provide a progressively-increasing hydraulic restraining force as each adjacent corrugation is encountered

The Mars Microprobe Mission: Advanced Micro-Avionics for Exploration Surface

Science.gov (United States)

Blue, Randel

2000-01-01

The Mars Microprobe Mission is the second spacecraft developed as part of the New Millennium Program deep space missions. The objective of the Microprobe Project is to demonstrate the applicability of key technologies for future planetary missions by developing two probes for deployment on Mars. The probes are designed with a single stage entry, descent, and landing system and impact the Martian surface at speeds of approximately 200 meters per second. The microprobes are composed of two main sections, a forebody section that penetrates to a depth below the Martian surface of 0.5 to 2 meters, and an aftbody section that remains on the surface. Each probe system consists of a number of advanced technology components developed specifically for this mission. These include a non-erosive aeroshell for entry into. the atmosphere, a set of low temperature batteries to supply probe power, an advanced microcontroller to execute the mission sequence, collect the science data, and react to possible system fault conditions, a telecommunications subsystem implemented on a set of custom integrated circuits, and instruments designed to provide science measurements from above and below the Martian surface. All of the electronic components have been designed and fabricated to withstand the severe impact shock environment and to operate correctly at predicted temperatures below -100 C.

Illumination Invariant Change Detection (iicd): from Earth to Mars

Science.gov (United States)

Wan, X.; Liu, J.; Qin, M.; Li, S. Y.

2018-04-01

Multi-temporal Earth Observation and Mars orbital imagery data with frequent repeat coverage provide great capability for planetary surface change detection. When comparing two images taken at different times of day or in different seasons for change detection, the variation of topographic shades and shadows caused by the change of sunlight angle can be so significant that it overwhelms the real object and environmental changes, making automatic detection unreliable. An effective change detection algorithm therefore has to be robust to the illumination variation. This paper presents our research on developing and testing an Illumination Invariant Change Detection (IICD) method based on the robustness of phase correlation (PC) to the variation of solar illumination for image matching. The IICD is based on two key functions: i) initial change detection based on a saliency map derived from pixel-wise dense PC matching and ii) change quantization which combines change type identification, motion estimation and precise appearance change identification. Experiment using multi-temporal Landsat 7 ETM+ satellite images, Rapid eye satellite images and Mars HiRiSE images demonstrate that our frequency based image matching method can reach sub-pixel accuracy and thus the proposed IICD method can effectively detect and precisely segment large scale change such as landslide as well as small object change such as Mars rover, under daily and seasonal sunlight changes.

Cryogenic Fluid Management Technology for Moon and Mars Missions

Science.gov (United States)

Doherty, Michael P.; Gaby, Joseph D.; Salerno, Louis J.; Sutherlin, Steven G.

2010-01-01

In support of the U.S. Space Exploration Policy, focused cryogenic fluid management technology efforts are underway within the National Aeronautics and Space Administration. Under the auspices of the Exploration Technology Development Program, cryogenic fluid management technology efforts are being conducted by the Cryogenic Fluid Management Project. Cryogenic Fluid Management Project objectives are to develop storage, transfer, and handling technologies for cryogens to support high performance demands of lunar, and ultimately, Mars missions in the application areas of propulsion, surface systems, and Earth-based ground operations. The targeted use of cryogens and cryogenic technologies for these application areas is anticipated to significantly reduce propellant launch mass and required on-orbit margins, to reduce and even eliminate storage tank boil-off losses for long term missions, to economize ground pad storage and transfer operations, and to expand operational and architectural operations at destination. This paper organizes Cryogenic Fluid Management Project technology efforts according to Exploration Architecture target areas, and discusses the scope of trade studies, analytical modeling, and test efforts presently underway, as well as future plans, to address those target areas. The target areas are: liquid methane/liquid oxygen for propelling the Altair Lander Ascent Stage, liquid hydrogen/liquid oxygen for propelling the Altair Lander Descent Stage and Ares V Earth Departure Stage, liquefaction, zero boil-off, and propellant scavenging for Lunar Surface Systems, cold helium and zero boil-off technologies for Earth-Based Ground Operations, and architecture definition studies for long term storage and on-orbit transfer and pressurization of LH2, cryogenic Mars landing and ascent vehicles, and cryogenic production via in situ resource utilization on Mars.

Practical gradient-descent for memristive crossbars

OpenAIRE

Nair, Manu V; Dudek, Piotr

2015-01-01

This paper discusses implementations of gradientdescent based learning algorithms on memristive crossbar arrays. The Unregulated Step Descent (USD) is described as a practical algorithm for feed-forward on-line training of large crossbar arrays. It allows fast feed-forward fully parallel on-line hardware based learning, without requiring accurate models of the memristor behaviour and precise control of the programming pulses. The effect of device parameters, training parameters, and device va...

Minimizing convex functions by continuous descent methods

Directory of Open Access Journals (Sweden)

Sergiu Aizicovici

2010-01-01

Full Text Available We study continuous descent methods for minimizing convex functions, defined on general Banach spaces, which are associated with an appropriate complete metric space of vector fields. We show that there exists an everywhere dense open set in this space of vector fields such that each of its elements generates strongly convergent trajectories.

Valles Marineris, Mars: High-Resolution Digital Terrain Model on the basis of Mars-Express HRSC data

Science.gov (United States)

Dumke, A.; Spiegel, M.; van Gasselt, S.; Neukum, G.

2009-04-01

Introduction: Since December 2003, the European Space Agency's (ESA) Mars Express (MEX) orbiter has been investigating Mars. The High Resolution Stereo Camera (HRSC), one of the scientific experiments onboard MEX, is a pushbroom stereo color scanning instrument with nine line detectors, each equipped with 5176 CCD sensor elements. Five CCD lines operate with panchromatic filters and four lines with red, green, blue and infrared filters at different observation angles [1]. MEX has a highly elliptical near-polar orbit and reaches a distance of 270 km at periapsis. Ground resolution of image data predominantly varies with respect to spacecraft altitude and the chosen macro-pixel format. Usually, although not exclusively, the nadir channel provides full resolution of up to 10 m per pixel. Stereo-, photometry and color channels generally have a coarser resolution. One of the goals for MEX HRSC is to cover Mars globally in color and stereoscopically at high-resolution. So far, HRSC has covered almost half of the surface of Mars at a resolution better than 20 meters per pixel. Such data are utilized to derive high resolution digital terrain models (DTM), ortho-image mosaics and additionally higher-level 3D data products such as 3D views. Standardized high-resolution single-strip digital terrain models (using improved orientation data) have been derived at the German Aerospace Center (DLR) in Berlin-Adlershof [2]. Those datasets, i.e. high-resolution digital terrain models as well as ortho-image data, are distributed as Vicar image files (http://www-mipl.jpl.nasa.gov/external/vicar.html) via the HRSCview web-interface [3], accessible at http://hrscview.fu-berlin.de. A systematic processing workflow is described in detail in [4,5]. In consideration of the scientific interest, the processing of the Valles Marineris region will be discussed in this paper. The DTM mosaic was derived from 82 HRSC orbits at approximately -22° S to 1° N and 250° to 311° E. Methods: Apart from

The grand descent has begun for CMS

CERN Multimedia

2006-01-01

Until recently, the CMS experimental cavern looked relatively empty; its detector was assembled entirely at ground level, to be lowered underground in 15 sections. On 2 November, the first hadronic forward calorimeter led the way with a grand descent. The first section of the CMS detector (centre of photo) arriving from the vertical shaft, viewed from the cavern floor. There is something unusual about the construction of the CMS detector. Instead of being built in the experimental cavern, like all the other detectors in the LHC experiments, it was constructed at ground level. This was to allow for easy access during the assembly of the detector and to minimise the size of the excavated cavern. The slightly nerve-wracking task of lowering it safely into the cavern in separate sections came after the complete detector was successfully tested with a magnetic field at ground level. In the early morning of 2 November, the first section of the CMS detector began its eagerly awaited descent into the underground ca...

Unique Spectroscopy and Imaging of Mars with the James Webb Space Telescope

Science.gov (United States)

Villanueva, Geronimo L.; Altieri, Francesca; Clancy, R. Todd; Encrenaz, Therese; Fouchet, Thierry; Hartogh, Paul; Lellouch, Emmanuel; Lopez-Valverde, Miguel A.; Mumma, Michael J.; Novak, Robert E.;

Planning fuel-conservative descents in an airline environmental using a small programmable calculator: algorithm development and flight test results

Energy Technology Data Exchange (ETDEWEB)

Knox, C.E.; Vicroy, D.D.; Simmon, D.A.

1985-05-01

A simple, airborne, flight-management descent algorithm was developed and programmed into a small programmable calculator. The algorithm may be operated in either a time mode or speed mode. The time mode was designed to aid the pilot in planning and executing a fuel-conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The speed model was designed for planning fuel-conservative descents when time is not a consideration. The descent path for both modes was calculated for a constant with considerations given for the descent Mach/airspeed schedule, gross weight, wind, wind gradient, and nonstandard temperature effects. Flight tests, using the algorithm on the programmable calculator, showed that the open-loop guidance could be useful to airline flight crews for planning and executing fuel-conservative descents.

Ethnic Identity and Acculturative Stress as Mediators of Depression in Students of Asian Descent

Science.gov (United States)

Lantrip, Crystal; Mazzetti, Francesco; Grasso, Joseph; Gill, Sara; Miller, Janna; Haner, Morgynn; Rude, Stephanie; Awad, Germine

2015-01-01

This study underscored the importance of addressing the well-being of college students of Asian descent, because these students had higher rates of depression and lower positive feelings about their ethnic group compared with students of European descent, as measured by the Affirmation subscale of the Ethnic Identity Scale. Affirmation mediated…

Random versus Deterministic Descent in RNA Energy Landscape Analysis

Directory of Open Access Journals (Sweden)

Luke Day

2016-01-01

Full Text Available Identifying sets of metastable conformations is a major research topic in RNA energy landscape analysis, and recently several methods have been proposed for finding local minima in landscapes spawned by RNA secondary structures. An important and time-critical component of such methods is steepest, or gradient, descent in attraction basins of local minima. We analyse the speed-up achievable by randomised descent in attraction basins in the context of large sample sets where the size has an order of magnitude in the region of ~106. While the gain for each individual sample might be marginal, the overall run-time improvement can be significant. Moreover, for the two nongradient methods we analysed for partial energy landscapes induced by ten different RNA sequences, we obtained that the number of observed local minima is on average larger by 7.3% and 3.5%, respectively. The run-time improvement is approximately 16.6% and 6.8% on average over the ten partial energy landscapes. For the large sample size we selected for descent procedures, the coverage of local minima is very high up to energy values of the region where the samples were randomly selected from the partial energy landscapes; that is, the difference to the total set of local minima is mainly due to the upper area of the energy landscapes.

Field reconnaissance geologic mapping of the Columbia Hills, Mars, based on Mars Exploration Rover Spirit and MRO HiRISE observations

Science.gov (United States)

Crumpler, L.S.; Arvidson, R. E.; Squyres, S. W.; McCoy, T.; Yingst, A.; Ruff, S.; Farrand, W.; McSween, Y.; Powell, M.; Ming, D. W.; Morris, R.V.; Bell, J.F.; Grant, J.; Greeley, R.; DesMarais, D.; Schmidt, M.; Cabrol, N.A.; Haldemann, A.; Lewis, K.W.; Wang, A.E.; Schroder, C.; Blaney, D.; Cohen, B.; Yen, A.; Farmer, J.; Gellert, Ralf; Guinness, E.A.; Herkenhoff, K. E.; Johnson, J. R.; Klingelhfer, G.; McEwen, A.; Rice, J.W.; Rice, M.; deSouza, P.; Hurowitz, J.

2011-01-01

Chemical, mineralogic, and lithologic ground truth was acquired for the first time on Mars in terrain units mapped using orbital Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (MRO HiRISE) image data. Examination of several dozen outcrops shows that Mars is geologically complex at meter length scales, the record of its geologic history is well exposed, stratigraphic units may be identified and correlated across significant areas on the ground, and outcrops and geologic relationships between materials may be analyzed with techniques commonly employed in terrestrial field geology. Despite their burial during the course of Martian geologic time by widespread epiclastic materials, mobile fines, and fall deposits, the selective exhumation of deep and well-preserved geologic units has exposed undisturbed outcrops, stratigraphic sections, and structural information much as they are preserved and exposed on Earth. A rich geologic record awaits skilled future field investigators on Mars. The correlation of ground observations and orbital images enables construction of a corresponding geologic reconnaissance map. Most of the outcrops visited are interpreted to be pyroclastic, impactite, and epiclastic deposits overlying an unexposed substrate, probably related to a modified Gusev crater central peak. Fluids have altered chemistry and mineralogy of these protoliths in degrees that vary substantially within the same map unit. Examination of the rocks exposed above and below the major unconformity between the plains lavas and the Columbia Hills directly confirms the general conclusion from remote sensing in previous studies over past years that the early history of Mars was a time of more intense deposition and modification of the surface. Although the availability of fluids and the chemical and mineral activity declined from this early period, significant later volcanism and fluid convection enabled additional, if localized, chemical activity

Videodefaecography combined with measurement of the anorectal angle and of perineal descent

International Nuclear Information System (INIS)

Skomorowska, E.; Henrichsen, S.; Christiansen, J.; Hegedues, V.; Glostrup Sygehus, Copenhagen

1987-01-01

Cineradiographic defaecography combined with measurement of the anorectal angle and descent of the pelvic floor is proposed. The method used in 73 women gave valuable information in 48 patients who complained of anal incompetence, rectal tenesmus, and chronic constipation. In these patients, high and low rectal intussusception, rectocele, and pathologic movement of the pelvic floor were detected. Some of these phenomena could only be diagnosed by the radiologic method here described. Quantitations of the anorectal angle and descent of the pelvic floor placed the group with constipation halfway between normal individuals and those with anal incompetence. The value of this finding is discussed. Recent improvements in anorectal surgery often make videodefaecography decisive for the choice of the optimal operative method. Therefore, videodefaecography together with measurement of the anorectal angle and pelvic floor descent is recommended whenever anorectal surgery for correction of functional disturbances is contemplated. (orig.)

Implementing planetary protection measures on the Mars Science Laboratory.

Science.gov (United States)

Benardini, James N; La Duc, Myron T; Beaudet, Robert A; Koukol, Robert

2014-01-01

The Mars Science Laboratory (MSL), comprising a cruise stage; an aeroshell; an entry, descent, and landing system; and the radioisotope thermoelectric generator-powered Curiosity rover, made history with its unprecedented sky crane landing on Mars on August 6, 2012. The mission's primary science objective has been to explore the area surrounding Gale Crater and assess its habitability for past life. Because microbial contamination could profoundly impact the integrity of the mission and compliance with international treaty was required, planetary protection measures were implemented on MSL hardware to verify that bioburden levels complied with NASA regulations. By applying the proper antimicrobial countermeasures throughout all phases of assembly, the total bacterial endospore burden of MSL at the time of launch was kept to 2.78×10⁵ spores, well within the required specification of less than 5.0×10⁵ spores. The total spore burden of the exposed surfaces of the landed MSL hardware was 5.64×10⁴, well below the allowed limit of 3.0×10⁵ spores. At the time of launch, the MSL spacecraft was burdened with an average of 22 spores/m², which included both planned landed and planned impacted hardware. Here, we report the results of a campaign to implement and verify planetary protection measures on the MSL flight system.

PHOENIX MARS MECA NON-IMAGING EDR V1.0

Data.gov (United States)

National Aeronautics and Space Administration — The Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) experiment on the Mars Phoenix Lander consists of four instrument components plus command...

Conjugate descent formulation of backpropagation error in feedforward neural networks

Directory of Open Access Journals (Sweden)

NK Sharma

2009-06-01

Full Text Available The feedforward neural network architecture uses backpropagation learning to determine optimal weights between different interconnected layers. This learning procedure uses a gradient descent technique applied to a sum-of-squares error function for the given input-output pattern. It employs an iterative procedure to minimise the error function for a given set of patterns, by adjusting the weights of the network. The first derivates of the error with respect to the weights identify the local error surface in the descent direction. Hence the network exhibits a different local error surface for every different pattern presented to it, and weights are iteratively modified in order to minimise the current local error. The determination of an optimal weight vector is possible only when the total minimum error (mean of the minimum local errors for all patterns from the training set may be minimised. In this paper, we present a general mathematical formulation for the second derivative of the error function with respect to the weights (which represents a conjugate descent for arbitrary feedforward neural network topologies, and we use this derivative information to obtain the optimal weight vector. The local error is backpropagated among the units of hidden layers via the second order derivative of the error with respect to the weights of the hidden and output layers independently and also in combination. The new total minimum error point may be evaluated with the help of the current total minimum error and the current minimised local error. The weight modification processes is performed twice: once with respect to the present local error and once more with respect to the current total or mean error. We present some numerical evidence that our proposed method yields better network weights than those determined via a conventional gradient descent approach.

A synthesis of Martian aqueous mineralogy after 1 Mars year of observations from the Mars Reconnaissance Orbiter

Science.gov (United States)

Murchie, S.L.; Mustard, J.F.; Ehlmann, B.L.; Milliken, R.E.; Bishop, J.L.; McKeown, N.K.; Noe Dobrea, E.Z.; Seelos, F.P.; Buczkowski, D.L.; Wiseman, S.M.; Arvidson, R. E.; Wray, J.J.; Swayze, G.; Clark, R.N.; Des Marais, D.J.; McEwen, A.S.; Bibring, J.-P.

2009-01-01

Martian aqueous mineral deposits have been examined and characterized using data acquired during Mars Reconnaissance Orbiter's (MRO) primary science phase, including Compact Reconnaissance Imaging Spectrometer for Mars hyperspectral images covering the 0.4-3.9 ??m wavelength range, coordinated with higher-spatial resolution HiRISE and Context Imager images. MRO's new high-resolution measurements, combined with earlier data from Thermal Emission Spectrometer; Thermal Emission Imaging System; and Observatoire pour la Min??ralogie, L'Eau, les Glaces et l'Activiti?? on Mars Express, indicate that aqueous minerals are both diverse and widespread on the Martian surface. The aqueous minerals occur in 9-10 classes of deposits characterized by distinct mineral assemblages, morphologies, and geologic settings. Phyllosilicates occur in several settings: in compositionally layered blankets hundreds of meters thick, superposed on eroded Noachian terrains; in lower layers of intracrater depositional fans; in layers with potential chlorides in sediments on intercrater plains; and as thousands of deep exposures in craters and escarpments. Carbonate-bearing rocks form a thin unit surrounding the Isidis basin. Hydrated silica occurs with hydrated sulfates in thin stratified deposits surrounding Valles Marineris. Hydrated sulfates also occur together with crystalline ferric minerals in thick, layered deposits in Terra Meridiani and in Valles Marineris and together with kaolinite in deposits that partially infill some highland craters. In this paper we describe each of the classes of deposits, review hypotheses for their origins, identify new questions posed by existing measurements, and consider their implications for ancient habitable environments. On the basis of current data, two to five classes of Noachian-aged deposits containing phyllosilicates and carbonates may have formed in aqueous environments with pH and water activities suitable for life. Copyright 2009 by the American

Efficient Sensor Placement Optimization Using Gradient Descent and Probabilistic Coverage

Directory of Open Access Journals (Sweden)

Vahab Akbarzadeh

2014-08-01

Full Text Available We are proposing an adaptation of the gradient descent method to optimize the position and orientation of sensors for the sensor placement problem. The novelty of the proposed method lies in the combination of gradient descent optimization with a realistic model, which considers both the topography of the environment and a set of sensors with directional probabilistic sensing. The performance of this approach is compared with two other black box optimization methods over area coverage and processing time. Results show that our proposed method produces competitive results on smaller maps and superior results on larger maps, while requiring much less computation than the other optimization methods to which it has been compared.

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;

Selection of the Mars Science Laboratory landing site

Science.gov (United States)

Golombek, M.; Grant, J.; Kipp, D.; Vasavada, A.; Kirk, Randolph L.; Fergason, Robin L.; Bellutta, P.; Calef, F.; Larsen, K.; Katayama, Y.; Huertas, A.; Beyer, R.; Chen, A.; Parker, T.; Pollard, B.; Lee, S.; Hoover, R.; Sladek, H.; Grotzinger, J.; Welch, R.; Dobrea, E. Noe; Michalski, J.; Watkins, M.

2012-01-01

The selection of Gale crater as the Mars Science Laboratory landing site took over five years, involved broad participation of the science community via five open workshops, and narrowed an initial >50 sites (25 by 20 km) to four finalists (Eberswalde, Gale, Holden and Mawrth) based on science and safety. Engineering constraints important to the selection included: (1) latitude (±30°) for thermal management of the rover and instruments, (2) elevation (surface that is safe for landing and roving and not dominated by fine-grained dust. Science criteria important for the selection include the ability to assess past habitable environments, which include diversity, context, and biosignature (including organics) preservation. Sites were evaluated in detail using targeted data from instruments on all active orbiters, and especially Mars Reconnaissance Orbiter. All of the final four sites have layered sedimentary rocks with spectral evidence for phyllosilicates that clearly address the science objectives of the mission. Sophisticated entry, descent and landing simulations that include detailed information on all of the engineering constraints indicate all of the final four sites are safe for landing. Evaluation of the traversabilty of the landing sites and target “go to” areas outside of the ellipse using slope and material properties information indicates that all are trafficable and “go to” sites can be accessed within the lifetime of the mission. In the final selection, Gale crater was favored over Eberswalde based on its greater diversity and potential habitability.

SU-E-I-75: Evaluation of An Orthopedic Metal Artifact Reduction (O-MAR) Algorithm On Patients with Spinal Prostheses Near Spinal Tumors

International Nuclear Information System (INIS)

Shen, Z; Xia, P; Djemil, T; Klahr, P

2014-01-01

Purpose: To evaluate the impact of a commercial orthopedic metal artifact reduction (O-MAR) algorithm on CT image quality and dose calculation for patients with spinal prostheses near spinal tumors. Methods: A CT electron density phantom was scanned twice: with tissue-simulating inserts only, and with a titanium insert replacing solid water. A patient plan was mapped to the phantom images in two ways: with the titanium inside or outside of the spinal tumor. Pinnacle and Eclipse were used to evaluate the dosimetric effects of O-MAR on 12-bit and 16-bit CT data, respectively. CT images from five patients with spinal prostheses were reconstructed with and without O-MAR. Two observers assessed the image quality improvement from O-MAR. Both pencil beam and Monte Carlo dose calculation in iPlan were used for the patient study. The percentage differences between non-OMAR and O-MAR datasets were calculated for PTV-min, PTV-max, PTV-mean, PTV-V100, PTV-D90, OAR-V10Gy, OAR-max, and OAR-D0.1cc. Results: O-MAR improved image quality but did not significantly affect the dose distributions and DVHs for both 12-bit and 16- bit CT phantom data. All five patient cases demonstrated some degree of image quality improvement from O-MAR, ranging from small to large metal artifact reduction. For pencil beam, the largest discrepancy was observed for OARV-10Gy at 5.4%, while the other seven parameters were ≤0.6%. For Monte Carlo, the differences between non-O-MAR and O-MAR datasets were ≤3.0%. Conclusion: Both phantom and patient studies indicated that O-MAR can substantially reduce metal artifacts on CT images, allowing better visualization of the anatomical structures and metal objects. The dosimetric impact of O-MAR was insignificant regardless of the metal location, image bit-depth, and dose calculation algorithm. O-MAR corrected images are recommended for radiation treatment planning on patients with spinal prostheses because of the improved image quality and no need to modify

Candidate cave entrances on Mars

Science.gov (United States)

Cushing, Glen E.

2012-01-01

This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visible-wavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.

Understanding the Convolutional Neural Networks with Gradient Descent and Backpropagation

Science.gov (United States)

Zhou, XueFei

2018-04-01

With the development of computer technology, the applications of machine learning are more and more extensive. And machine learning is providing endless opportunities to develop new applications. One of those applications is image recognition by using Convolutional Neural Networks (CNNs). CNN is one of the most common algorithms in image recognition. It is significant to understand its theory and structure for every scholar who is interested in this field. CNN is mainly used in computer identification, especially in voice, text recognition and other aspects of the application. It utilizes hierarchical structure with different layers to accelerate computing speed. In addition, the greatest features of CNNs are the weight sharing and dimension reduction. And all of these consolidate the high effectiveness and efficiency of CNNs with idea computing speed and error rate. With the help of other learning altruisms, CNNs could be used in several scenarios for machine learning, especially for deep learning. Based on the general introduction to the background and the core solution CNN, this paper is going to focus on summarizing how Gradient Descent and Backpropagation work, and how they contribute to the high performances of CNNs. Also, some practical applications will be discussed in the following parts. The last section exhibits the conclusion and some perspectives of future work.

Revised coordinates of the Mars Orbiter Laser Altimeter (MOLA) footprints

Science.gov (United States)

Annibali, S.; Stark, A.; Gwinner, K.; Hussmann, H.; Oberst, J.

2017-09-01

We revised the Mars Orbiter Laser Altimeter (MOLA) footprint locations (i.e. areocentric body-fixed latitude and longitude), using updated trajectory models for the Mars Global Surveyor and updated rotation parameters of Mars, including precession, nutation and length-of-day variation. We assess the impact of these updates on the gridded MOLA maps. A first comparison reveals that even slight corrections to the rotational state of Mars can lead to height differences up to 100 m (in particular in regions with high slopes, where large interpolation effects are expected). Ultimately, we aim at independent measurements of the rotation parameters of Mars. We co-register MOLA profiles to digital terrain models from stereo images (stereo DTMs) and measure offsets of the two data sets.

Implementing a Science-driven Mars Exploration Program

Science.gov (United States)

Garvin, J. B.

2001-12-01

NASA's newly restructured Mars Exploration Program (MEP) was developed on the basis of the goals, objectives, investigations, and prioritizations established by the Mars Exploration Payload Analysis Group (as summarized previously by Greeley et al., 2001). The underlying scientific strategy is linked to common threads which include the many roles water has played on and within Mars as a "system". The implementation strategy that has been adopted relies heavily on an ever-sharpening program of reconnaissance, beginning with the legacy of the Mars Global Surveyor, continuing with the multispectral and compositional observations of the Mars Odyssey orbiter, and extending to a first step in surface-based reconnaissance with the 2003 Mars Exploration Rovers. The results of MGS and Odyssey will serve to focus the trade space of localities where the record, for example, of persistent surface water may have been preserved in a mineralogical sense. The 2005 Mars Reconnaissance Orbiter will further downselect the subset of sites on Mars where evidence of depositional patterns and aqueous mineralogies (i.e., diagenetic minerals) are most striking at scales as fine as tens to hundreds of meters. Reconnaissance will move to the surface and shallow subsurface in 2007 with the Mars "Smart Lander" (MSL), at which time an extensive array of mobile scientific exploration tools will be used to examine a locality at 10km traverse scales, ultimately asking scientific questions which can be classed as paleobiological (i.e., life inference). Further orbital reconnaissance may be undertaken in 2009, perhaps involving targeted multi-wavelength SAR imaging, in anticipation of a precisely targeted Mars Sample Return mission as early as 2011. This sequence of core program MEP missions will be amplified by the selection of PI-led SCOUT missions, starting in 2007, and continuing every other Mars launch opportunity.

Analysis of local slopes at the InSight landing site on Mars

Science.gov (United States)

Fergason, Robin L.; Kirk, Randolph L.; Cushing, Glen; Galuszka, Donna M.; Golombek, Matthew P.; Hare, Trent M.; Howington-Kraus, Elpitha; Kipp, Devin M; Redding, Bonnie L.

2017-01-01

To evaluate the topography of the surface within the InSight candidate landing ellipses, we generated Digital Terrain Models (DTMs) at lander scales and those appropriate for entry, descent, and landing simulations, along with orthoimages of both images in each stereopair, and adirectional slope images. These products were used to assess the distribution of slopes for each candidate ellipse and terrain type in the landing site region, paying particular attention to how these slopes impact InSight landing and engineering safety, and results are reported here. Overall, this region has extremely low slopes at 1-meter baseline scales and meets the safety constraints of the InSight lander. The majority of the landing ellipse has a mean slope at 1-meter baselines of 3.2°. In addition, a mosaic of HRSC, CTX, and HiRISE DTMs within the final landing ellipse (ellipse 9) was generated to support entry, descent, and landing simulations and evaluations. Several methods were tested to generate this mosaic and the NASA Ames Stereo Pipeline program dem_mosaic produced the best results. For the HRSC-CTX-HiRISE DTM mosaic, more than 99 % of the mosaic has slopes less than 15°, and the introduction of artificially high slopes along image seams was minimized.

Applying Gradient Descent in Convolutional Neural Networks

Science.gov (United States)

Cui, Nan

2018-04-01

With the development of the integrated circuit and computer science, people become caring more about solving practical issues via information technologies. Along with that, a new subject called Artificial Intelligent (AI) comes up. One popular research interest of AI is about recognition algorithm. In this paper, one of the most common algorithms, Convolutional Neural Networks (CNNs) will be introduced, for image recognition. Understanding its theory and structure is of great significance for every scholar who is interested in this field. Convolution Neural Network is an artificial neural network which combines the mathematical method of convolution and neural network. The hieratical structure of CNN provides it reliable computer speed and reasonable error rate. The most significant characteristics of CNNs are feature extraction, weight sharing and dimension reduction. Meanwhile, combining with the Back Propagation (BP) mechanism and the Gradient Descent (GD) method, CNNs has the ability to self-study and in-depth learning. Basically, BP provides an opportunity for backwardfeedback for enhancing reliability and GD is used for self-training process. This paper mainly discusses the CNN and the related BP and GD algorithms, including the basic structure and function of CNN, details of each layer, the principles and features of BP and GD, and some examples in practice with a summary in the end.

Machine learning for inverse lithography: using stochastic gradient descent for robust photomask synthesis

International Nuclear Information System (INIS)

Jia, Ningning; Lam, Edmund Y

2010-01-01

Inverse lithography technology (ILT) synthesizes photomasks by solving an inverse imaging problem through optimization of an appropriate functional. Much effort on ILT is dedicated to deriving superior masks at a nominal process condition. However, the lower k 1 factor causes the mask to be more sensitive to process variations. Robustness to major process variations, such as focus and dose variations, is desired. In this paper, we consider the focus variation as a stochastic variable, and treat the mask design as a machine learning problem. The stochastic gradient descent approach, which is a useful tool in machine learning, is adopted to train the mask design. Compared with previous work, simulation shows that the proposed algorithm is effective in producing robust masks

Correlation Between Echodefecography and 3-Dimensional Vaginal Ultrasonography in the Detection of Perineal Descent in Women With Constipation Symptoms.

Science.gov (United States)

Murad-Regadas, Sthela M; Pinheiro Regadas, Francisco Sergio; Rodrigues, Lusmar V; da Silva Vilarinho, Adjra; Buchen, Guilherme; Borges, Livia Olinda; Veras, Lara B; da Cruz, Mariana Murad

2016-12-01

Defecography is an established method of evaluating dynamic anorectal dysfunction, but conventional defecography does not allow for visualization of anatomic structures. The purpose of this study was to describe the use of dynamic 3-dimensional endovaginal ultrasonography for evaluating perineal descent in comparison with echodefecography (3-dimensional anorectal ultrasonography) and to study the relationship between perineal descent and symptoms and anatomic/functional abnormalities of the pelvic floor. This was a prospective study. The study was conducted at a large university tertiary care hospital. Consecutive female patients were eligible if they had pelvic floor dysfunction, obstructed defecation symptoms, and a score >6 on the Cleveland Clinic Florida Constipation Scale. Each patient underwent both echodefecography and dynamic 3-dimensional endovaginal ultrasonography to evaluate posterior pelvic floor dysfunction. Normal perineal descent was defined on echodefecography as puborectalis muscle displacement ≤2.5 cm; excessive perineal descent was defined as displacement >2.5 cm. Of 61 women, 29 (48%) had normal perineal descent; 32 (52%) had excessive perineal descent. Endovaginal ultrasonography identified 27 of the 29 patients in the normal group as having anorectal junction displacement ≤1 cm (mean = 0.6 cm; range, 0.1-1.0 cm) and a mean anorectal junction position of 0.6 cm (range, 0-2.3 cm) above the symphysis pubis during the Valsalva maneuver and correctly identified 30 of the 32 patients in the excessive perineal descent group. The κ statistic showed almost perfect agreement (κ = 0.86) between the 2 methods for categorization into the normal and excessive perineal descent groups. Perineal descent was not related to fecal or urinary incontinence or anatomic and functional factors (sphincter defects, pubovisceral muscle defects, levator hiatus area, grade II or III rectocele, intussusception, or anismus). The study did not include a

Descent in buildings (AM-190)

CERN Document Server

Mühlherr, Bernhard; Weiss, Richard M

2015-01-01

Descent in Buildings begins with the resolution of a major open question about the local structure of Bruhat-Tits buildings. The authors then put their algebraic solution into a geometric context by developing a general fixed point theory for groups acting on buildings of arbitrary type, giving necessary and sufficient conditions for the residues fixed by a group to form a kind of subbuilding or "form" of the original building. At the center of this theory is the notion of a Tits index, a combinatorial version of the notion of an index in the relative theory of algebraic groups. These results

Mid-Latitude versus Polar-Latitude Transitional Impact Craters: Geometric Properties from Mars Orbiter Laser Altimeter (MOLA) Observations and Viking Images

Science.gov (United States)

Matias, A.; Garvin, J. B.; Sakimoto, S. E. H.

1998-01-01

One intriguing aspect of martian impact crater morphology is the change of crater cavity and ejecta characteristics from the mid-latitudes to the polar regions. This is thought to reflect differences in target properties such as an increasing presence of ice in the polar regions. Previous image-based efforts concerning martian crater morphology has documented some aspects of this, but has been hampered by the lack of adequate topography data. Recent Mars Orbiter Laser Altimeter (MOLA) topographic profiles provide a quantitative perspective for interpreting the detailed morphologies of martian crater cavities and ejecta morphology. This study is a preliminary effort to quantify the latitude-dependent differences in morphology with the goal of identifying target-dependent and crater modification effects from the combined of images and MOLA topography. We combine the available MOLA profiles and the corresponding Viking Mars Digital Image Mosaics (MDIMS), and high resolution Viking Orbiter images to focus on two transitional craters; one on the mid-latitudes, and one in the North Polar region. One MOLA pass (MGS Orbit 34) traverses the center of a 15.9 km diameter fresh complex crater located at 12.8degN 83.8degE on the Hesperian ridge plains unit (Hvr). Viking images, as well as MOLA data, show that this crater has well developed wall terraces and a central peak with 429 m of relative relief. Three MOLA passes have been acquired for a second impact crater, which is located at 69.5degN 41degE on the Vastitas Borealis Formation. This fresh rampart crater lacks terraces and central peak structures and it has a depth af 579 m. Correlation between images and MOLA topographic profiles allows us to construct basic facies maps of the craters. Eight main units were identified, four of which are common on both craters.

Mars Public Mapping Project: Public Participation in Science Research; Providing Opportunities for Kids of All Ages

Science.gov (United States)

Rogers, L. D.; Valderrama Graff, P.; Bandfield, J. L.; Christensen, P. R.; Klug, S. L.; Deva, B.; Capages, C.

2007-12-01

The Mars Public Mapping Project is a web-based education and public outreach tool developed by the Mars Space Flight Facility at Arizona State University. This tool allows the general public to identify and map geologic features on Mars, utilizing Thermal Emission Imaging System (THEMIS) visible images, allowing public participation in authentic scientific research. In addition, participants are able to rate each image (based on a 1 to 5 star scale) to help build a catalog of some of the more appealing and interesting martian surface features. Once participants have identified observable features in an image, they are able to view a map of the global distribution of the many geologic features they just identified. This automatic feedback, through a global distribution map, allows participants to see how their answers compare to the answers of other participants. Participants check boxes "yes, no, or not sure" for each feature that is listed on the Mars Public Mapping Project web page, including surface geologic features such as gullies, sand dunes, dust devil tracks, wind streaks, lava flows, several types of craters, and layers. Each type of feature has a quick and easily accessible description and example image. When a participant moves their mouse over each example thumbnail image, a window pops up with a picture and a description of the feature. This provides a form of "on the job training" for the participants that can vary with their background level. For users who are more comfortable with Mars geology, there is also an advanced feature identification section accessible by a drop down menu. This includes additional features that may be identified, such as streamlined islands, valley networks, chaotic terrain, yardangs, and dark slope streaks. The Mars Public Mapping Project achieves several goals: 1) It engages the public in a manner that encourages active participation in scientific research and learning about geologic features and processes. 2) It helps to

Investigation of small scale roughness properties of Martian terrains using Mars Reconnaissance Orbiter data.

Science.gov (United States)

Ivanov, A. B.; Rossi, A.

2009-04-01

Studies of layered terrains in polar regions as well as inside craters and other areas on Mars often require knowledge of local topography at much finer resolution than global MOLA topography allows. For example, in the polar layered deposits spatial relationships are important to understand unconformities that are observed on the edges of the layered terrains [15,3]. Their formation process is not understood at this point, yet fine scale topography, joint with ground penetrating radar like SHARAD and MARSIS may shed light on their 3D structure. Landing site analysis also requires knowledge of local slopes and roughness at scales from 1 to 10 m [1,2]. Mars Orbiter Camera [13] has taken stereo images at these scales, however interpretation was difficult due to unstable behavior of the Mars Global Surveyor spacecraft during image take (wobbling effect). Mars Reconnaissance Orbiter (MRO) is much better stabilized, since it is required for optimal operation of its high resolution camera. In this work we have utilized data from MRO sensors (CTX camera [11] and HIRISE camera [12] in order to derive digital elevation models (DEM) from images targeted as stereo pairs. We employed methods and approaches utilized for the Mars Orbiter Camera (MOC) stereo data [4,5]. CTX data varies in resolution and stereo pairs analyzed in this work can be derived at approximately 10m scale. HIRISE images allow DEM post spacing at around 1 meter. The latter are very big images and our computer infrastructure was only able to process either reduced resolution images, covering larger surface or working with smaller patches at the original resolution. We employed stereo matching technique described in [5,9], in conjunction with radiometric and geometric image processing in ISIS3 [16]. This technique is capable of deriving tiepoint co-registration at subpixel precision and has proven itself when used for Pathfinder and MER operations [8]. Considerable part of this work was to accommodate CTX and

Reversible cerebral vasoconstriction syndrome precipitated by airplane descent: Case report.

Science.gov (United States)

Hiraga, Akiyuki; Aotsuka, Yuya; Koide, Kyosuke; Kuwabara, Satoshi

2017-10-01

Background Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by segmental vasospasm. Vasoactive agents and childbirth have been reported as precipitating factors for RCVS; however, RCVS induced by altitude change or air travel has rarely been reported. Case We present a case of a 74-year-old woman who presented with thunderclap headache during airplane descent. Magnetic resonance angiography demonstrated segmental vasoconstriction that improved 9 days after onset. Conclusion These findings indicate that airplane descent may be a trigger of RCVS. The time course of headache in the present case was similar to that of prolonged headache attributed to airplane travel, indicating that RCVS during air travel may have previously been overlooked and that some headache attributed to airplane travel cases may represent a milder form of RCVS.

An Undergraduate Endeavor: Assembling a Live Planetarium Show About Mars

Science.gov (United States)

McGraw, Allison M.

2016-10-01

Viewing the mysterious red planet Mars goes back thousands of years with just the human eye but in more recent years the growth of telescopes, satellites and lander missions unveil unrivaled detail of the Martian surface that tells a story worth listening to. This planetarium show will go through the observations starting with the ancients to current understandings of the Martian surface, atmosphere and inner-workings through past and current Mars missions. Visual animations of its planetary motions, display of high resolution images from the Hi-RISE (High Resolution Imaging Science Experiment) and CTX (Context Camera) data imagery aboard the MRO (Mars Reconnaissance Orbiter) as well as other datasets will be used to display the terrain detail and imagery of the planet Mars with a digital projection system. Local planetary scientists and Mars specialists from the Lunar and Planetary Lab at the University of Arizona (Tucson, AZ) will be interviewed and used in the show to highlight current technology and understandings of the red planet. This is an undergraduate project that is looking for collaborations and insight in order gain structure in script writing that will teach about this planetary body to all ages in the format of a live planetarium show.

Nonlinear System Identification Using Neural Networks Trained with Natural Gradient Descent

Directory of Open Access Journals (Sweden)

Ibnkahla Mohamed

2003-01-01

Full Text Available We use natural gradient (NG learning neural networks (NNs for modeling and identifying nonlinear systems with memory. The nonlinear system is comprised of a discrete-time linear filter followed by a zero-memory nonlinearity . The NN model is composed of a linear adaptive filter followed by a two-layer memoryless nonlinear NN. A Kalman filter-based technique and a search-and-converge method have been employed for the NG algorithm. It is shown that the NG descent learning significantly outperforms the ordinary gradient descent and the Levenberg-Marquardt (LM procedure in terms of convergence speed and mean squared error (MSE performance.

Gender differences of sagittal knee and ankle biomechanics during stair-to-ground descent transition.

Science.gov (United States)

Hong, Yoon No Gregory; Shin, Choongsoo S

2015-12-01

Falls on stairs often result in severe injury and occur twice as frequently in women. However, gender differences in kinetics and kinematics during stair descent are unknown. Thus, this study aimed to determine whether gender differences of knee and ankle biomechanics exist in the sagittal plane during the stair-to-ground descending transition. It was hypothesized that 1) women would reveal higher ground-toe-trochanter angle and lower ground-toe length during stair-to-ground descent transition than men; and 2) women would reveal lower peak knee extension moment during stair-to-ground descent transition than men. Fifteen men and fifteen women were recruited and performed a stair descent activity. Kinetic and kinematic data were obtained using a force plate and motion capture system. The women performed the stair descent with a lower peak knee extension moment and a peak knee power at the early weight acceptance phase. The women also revealed a higher ground-toe-trochanter angle and a lower ground-toe length, which indicated a more forward position of the lower extremity relative to the toe contact point at both the initial contact and at the time of peak kinematic and kinetic events. This study found that knee and ankle kinematics and kinetics differed significantly between the genders due to differences in ground-toe-trochanter angle. Women have a different stair descending strategy that reduces the demand of the lower extremity muscle function, but this strategy seems to increase the risk of falls. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mars, accessing the third dimension: a software tool to exploit Mars ground penetrating radars data.

Science.gov (United States)

Cantini, Federico; Ivanov, Anton B.

2016-04-01

The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), on board the ESA's Mars Express and the SHAllow RADar (SHARAD), on board the NASA's Mars Reconnaissance Orbiter are two ground penetrating radars (GPRs) aimed to probe the crust of Mars to explore the subsurface structure of the planet. By now they are collecting data since about 10 years covering a large fraction of the Mars surface. On the Earth GPRs collect data by sending electromagnetic (EM) pulses toward the surface and listening to the return echoes occurring at the dielectric discontinuities on the planet's surface and subsurface. The wavelengths used allow MARSIS EM pulses to penetrate the crust for several kilometers. The data products (Radargrams) are matrices where the x-axis spans different sampling points on the planet surface and the y-axis is the power of the echoes over time in the listening window. No standard way to manage this kind of data is established in the planetary science community and data analysis and interpretation require very often some knowledge of radar signal processing. Our software tool is aimed to ease the access to this data in particular to scientists without a specific background in signal processing. MARSIS and SHARAD geometrical data such as probing point latitude and longitude and spacecraft altitude, are stored, together with relevant acquisition metadata, in a geo-enabled relational database implemented using PostgreSQL and PostGIS. Data are extracted from official ESA and NASA released data using self-developed python classes and scripts and inserted in the database using OGR utilities. This software is also aimed to be the core of a collection of classes and script to implement more complex GPR data analysis. Geometrical data and metadata are exposed as WFS layers using a QGIS server, which can be further integrated with other data, such as imaging, spectroscopy and topography. Radar geometry data will be available as a part of the iMars Web

Reference-shaping adaptive control by using gradient descent optimizers.

Directory of Open Access Journals (Sweden)

Baris Baykant Alagoz

Full Text Available This study presents a model reference adaptive control scheme based on reference-shaping approach. The proposed adaptive control structure includes two optimizer processes that perform gradient descent optimization. The first process is the control optimizer that generates appropriate control signal for tracking of the controlled system output to a reference model output. The second process is the adaptation optimizer that performs for estimation of a time-varying adaptation gain, and it contributes to improvement of control signal generation. Numerical update equations derived for adaptation gain and control signal perform gradient descent optimization in order to decrease the model mismatch errors. To reduce noise sensitivity of the system, a dead zone rule is applied to the adaptation process. Simulation examples show the performance of the proposed Reference-Shaping Adaptive Control (RSAC method for several test scenarios. An experimental study demonstrates application of method for rotor control.

Wet Mars, Dry Mars

Science.gov (United States)

Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Yan, D.; Fricke, K. W.; Thrall, L.

2012-12-01

The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This poster highlights the third in a series of presentations that target school-age audiences with the overall goal of helping the audience visualize planetary magnetic field and understand how they can impact the climatic evolution of a planet. Our first presentation, "Goldilocks and the Three Planets," targeted to elementary school age audiences, focuses on the differences in the atmospheres of Venus, Earth, and Mars and the causes of the differences. The second presentation, "Lost on Mars (and Venus)," geared toward a middle school age audience, highlights the differences in the magnetic fields of these planets and what we can learn from these differences. Finally, in the third presentation, "Wet Mars, Dry Mars," targeted to high school age audiences and the focus of this poster, the emphasis is on the long term climatic affects of the presence or absence of a magnetic field using the contrasts between Earth and Mars. These presentations are given using visually engaging spherical displays in conjunction with hands-on activities and scientifically accurate 3D models of planetary magnetic fields. We will summarize the content of our presentations, discuss our lessons learned from evaluations, and show (pictures of) our hands-on activities and 3D models.

Special section introduction on MicroMars to MegaMars

Science.gov (United States)

Bridges, Nathan T.; Dundas, Colin M.; Edgar, Lauren

2016-01-01

The study of Earth's surface and atmosphere evolved from local investigations to the incorporation of remote sensing on a global scale. The study of Mars has followed the opposite progression, beginning with telescopic observations, followed by flyby and orbital missions, landers, and finally rover missions in the last ∼20 years. This varied fleet of spacecraft (seven of which are currently operating as of this writing) provides a rich variety of datasets at spatial scales ranging from microscopic images to synoptic orbital remote sensing.

Aeolian sedimentary processes at the Bagnold Dunes, Mars: Implications for modern dune dynamics and sedimentary structures in the aeolian stratigraphic record of Mars

Science.gov (United States)

Ewing, Ryan C.; Bridges, Nathan T.; Sullivan, Rob; Lapotre, Mathieu G. A.; Fischer, Woodward W.; Lamb, Mike P.; Rubin, David M.; Lewis, Kevin W.; Gupta, Sanjeev

2016-04-01

Wind-blown sand dunes are ubiquitous on the surface of Mars and are a recognized component of the martian stratigraphic record. Our current knowledge of the aeolian sedimentary processes that determine dune morphology, drive dune dynamics, and create aeolian cross-stratification are based upon orbital studies of ripple and dune morphodynamics, rover observations of stratification on Mars, Earth analogs, and experimental and theoretical studies of sand movement under Martian conditions. In-situ observations of sand dunes (informally called the Bagnold Dunes) by Curiosity Rover in Gale Crater, Mars provide the first opportunity to make observations of dunes from the grain-to-dune scale thereby filling the gap in knowledge between theory and orbital observations and refining our understanding of the martian aeolian stratigraphic record. We use the suite of cameras on Curiosity, including Navigation Camera (Navcam), Mast Camera (Mastcam) and Mars Hand Lens Imager (MAHLI), to make observations of the Bagnold Dunes. Measurements of sedimentary structures are made where stereo images are available. Observations indicate that structures generated by gravity-driven processes on the dune lee slopes, such as grainflow and grainfall, are similar to the suite of aeolian sedimentary structures observed on Earth and should be present and recognizable in Mars' aeolian stratigraphic record. Structures formed by traction-driven processes deviate significantly from those found on Earth. The dune hosts centimeter-scale wind ripples and large, meter-scale ripples, which are not found on Earth. The large ripples migrate across the depositional, lee slopes of the dune, which implies that these structures should be present in Mars' stratigraphic record and may appear similar to compound-dune stratification.The Mars Science Laboratory Curiosity Rover Team is acknowledged for their support of this work.

Real-time aircraft continuous descent trajectory optimization with ATC time constraints using direct collocation methods.

OpenAIRE

Verhoeven, Ronald; Dalmau Codina, Ramon; Prats Menéndez, Xavier; de Gelder, Nico

2014-01-01

1 Abstract In this paper an initial implementation of a real - time aircraft trajectory optimization algorithm is presented . The aircraft trajectory for descent and approach is computed for minimum use of thrust and speed brake in support of a “green” continuous descent and approach flight operation, while complying with ATC time constraints for maintaining runway throughput and co...

Fluvial processes on Mars: Erosion and sedimentation

Science.gov (United States)

Squyres, Steven W.

1988-01-01

One of the most important discoveries of the Mariner 9 and Viking missions to Mars was evidence of change of the Martian surface by the action of liquid water. From the standpoint of a Mars Rover/Sample Return Mission, fluvial activity on Mars is important in two ways: (1) channel formation has deeply eroded the Martian crust, providing access to relatively undisturbed subsurface units; and (2) much of the material eroded from channels may have been deposited in standing bodies of liquid water. The most striking fluvial erosion features on Mars are the outflow channels. A second type of channel apparently caused by flow of liquid water is the valley systems. These are similar to terrestial drainage systems. The sedimentary deposits of outflow channels are often difficult to identfy. No obvious deposits such as deltaic accumulations are visible in Viking images. Another set of deposits that may be water lain and that date approx. from the epoch of outflow channels are the layered deposits in the Valles Marineris. From the standpoint of a Mars Rover/Sample Return mission, the problem with all of these water-lain sediments is their age, or rather the lack of it.

SU-F-I-49: Vendor-Independent, Model-Based Iterative Reconstruction On a Rotating Grid with Coordinate-Descent Optimization for CT Imaging Investigations

International Nuclear Information System (INIS)

Young, S; Hoffman, J; McNitt-Gray, M; Noo, F

2016-01-01

Purpose: Iterative reconstruction methods show promise for improving image quality and lowering the dose in helical CT. We aim to develop a novel model-based reconstruction method that offers potential for dose reduction with reasonable computation speed and storage requirements for vendor-independent reconstruction from clinical data on a normal desktop computer. Methods: In 2012, Xu proposed reconstructing on rotating slices to exploit helical symmetry and reduce the storage requirements for the CT system matrix. Inspired by this concept, we have developed a novel reconstruction method incorporating the stored-system-matrix approach together with iterative coordinate-descent (ICD) optimization. A penalized-least-squares objective function with a quadratic penalty term is solved analytically voxel-by-voxel, sequentially iterating along the axial direction first, followed by the transaxial direction. 8 in-plane (transaxial) neighbors are used for the ICD algorithm. The forward problem is modeled via a unique approach that combines the principle of Joseph’s method with trilinear B-spline interpolation to enable accurate reconstruction with low storage requirements. Iterations are accelerated with multi-CPU OpenMP libraries. For preliminary evaluations, we reconstructed (1) a simulated 3D ellipse phantom and (2) an ACR accreditation phantom dataset exported from a clinical scanner (Definition AS, Siemens Healthcare). Image quality was evaluated in the resolution module. Results: Image quality was excellent for the ellipse phantom. For the ACR phantom, image quality was comparable to clinical reconstructions and reconstructions using open-source FreeCT-wFBP software. Also, we did not observe any deleterious impact associated with the utilization of rotating slices. The system matrix storage requirement was only 4.5GB, and reconstruction time was 50 seconds per iteration. Conclusion: Our reconstruction method shows potential for furthering research in low

SU-F-I-49: Vendor-Independent, Model-Based Iterative Reconstruction On a Rotating Grid with Coordinate-Descent Optimization for CT Imaging Investigations

Energy Technology Data Exchange (ETDEWEB)

Young, S; Hoffman, J; McNitt-Gray, M [UCLA School of Medicine, Los Angeles, CA (United States); Noo, F [University of Utah, Salt Lake City, UT (United States)

2016-06-15

Purpose: Iterative reconstruction methods show promise for improving image quality and lowering the dose in helical CT. We aim to develop a novel model-based reconstruction method that offers potential for dose reduction with reasonable computation speed and storage requirements for vendor-independent reconstruction from clinical data on a normal desktop computer. Methods: In 2012, Xu proposed reconstructing on rotating slices to exploit helical symmetry and reduce the storage requirements for the CT system matrix. Inspired by this concept, we have developed a novel reconstruction method incorporating the stored-system-matrix approach together with iterative coordinate-descent (ICD) optimization. A penalized-least-squares objective function with a quadratic penalty term is solved analytically voxel-by-voxel, sequentially iterating along the axial direction first, followed by the transaxial direction. 8 in-plane (transaxial) neighbors are used for the ICD algorithm. The forward problem is modeled via a unique approach that combines the principle of Joseph’s method with trilinear B-spline interpolation to enable accurate reconstruction with low storage requirements. Iterations are accelerated with multi-CPU OpenMP libraries. For preliminary evaluations, we reconstructed (1) a simulated 3D ellipse phantom and (2) an ACR accreditation phantom dataset exported from a clinical scanner (Definition AS, Siemens Healthcare). Image quality was evaluated in the resolution module. Results: Image quality was excellent for the ellipse phantom. For the ACR phantom, image quality was comparable to clinical reconstructions and reconstructions using open-source FreeCT-wFBP software. Also, we did not observe any deleterious impact associated with the utilization of rotating slices. The system matrix storage requirement was only 4.5GB, and reconstruction time was 50 seconds per iteration. Conclusion: Our reconstruction method shows potential for furthering research in low

Machado-Joseph Disease in Pedigrees of Azorean descent is Linked to Chromosome 14

OpenAIRE

George-Hyslop, P. St; Rogaeva, E.; Huterer, J.; Tsuda, T.; Santos, J.; Haines, J. L.; Schlumpf, K.; Rogaev, E. I.; Liang, Y.; McLachlan, D. R. Crapper; Kennedy, J.; Weissenbach, J.; Billingsley, G. D.; Cox, D. W.; Lang, A. E.

1994-01-01

A locus for Machado-Joseph disease (MJD) has recently been mapped to a 30-cM region of chromosome 14q in five pedigrees of Japanese descent. MJD is a clinically pleomorphic neurodegenerative disease that was originally described in subjects of Azorean descent. In light of the nonallelic heterogeneity in other inherited spinocere-bellar ataxias, we were interested to determine if the MJD phenotype in Japanese and Azorean pedigrees arose from mutations at the same locus. We provide evidence tha...

Surface-based 3D measurements of small aeolian bedforms on Mars and implications for estimating ExoMars rover traversability hazards

Science.gov (United States)

Balme, Matt; Robson, Ellen; Barnes, Rob; Butcher, Frances; Fawdon, Peter; Huber, Ben; Ortner, Thomas; Paar, Gerhard; Traxler, Christoph; Bridges, John; Gupta, Sanjeev; Vago, Jorge L.

2018-04-01

Recent aeolian bedforms comprising loose sand are common on the martian surface and provide a mobility hazard to Mars rovers. The ExoMars rover will launch in 2020 to one of two candidate sites: Mawrth Vallis or Oxia Planum. Both sites contain numerous aeolian bedforms with simple ripple-like morphologies. The larger examples are 'Transverse Aeolian Ridges' (TARs), which stereo imaging analyses have shown to be a few metres high and up to a few tens of metres across. Where they occur, TARs therefore present a serious, but recognized and avoidable, rover mobility hazard. There also exists a population of smaller bedforms of similar morphology, but it is unknown whether these bedforms will be traversable by the ExoMars rover. We informally refer to these bedforms as "mini-TARs", as they are about an order of magnitude smaller than most TARs observed to date. They are more abundant than TARs in the Oxia Planum site, and can be pervasive in areas. The aim of this paper is to estimate the heights of these features, which are too small to measured using High Resolution Imaging Science Experiment (HiRISE) Digital Elevation Models (DEMs), from orbital data alone. Thereby, we aim to increase our knowledge of the hazards in the proposed ExoMars landing sites. We propose a methodology to infer the height of these mini-TARs based on comparisons with similar features observed by previous Mars rovers. We use rover-based stereo imaging from the NASA Mars Exploration Rover (MER) Opportunity and PRo3D software, a 3D visualisation and analysis tool, to measure the size and height of mini-TARs in the Meridiani Planum region of Mars. These are good analogues for the smaller bedforms at the ExoMars rover candidate landing sites. We show that bedform height scales linearly with length (as measured across the bedform, perpendicular to the crest ridge) with a ratio of about 1:15. We also measured the lengths of many of the smaller aeolian bedforms in the ExoMars rover Oxia Planum

NASA Mars Conference

International Nuclear Information System (INIS)

Reiber, D.B.

1988-01-01

Papers about Mars and Mars exploration are presented, covering topics such as Martian history, geology, volcanism, channels, moons, atmosphere, meteorology, water on the planet, and the possibility of life. The unmanned exploration of Mars is discussed, including the Phobos Mission, the Mars Observer, the Mars Aeronomy Observer, the seismic network, Mars sample return missions, and the Mars Ball, an inflatable-sectored-tire rover concept. Issues dealing with manned exploration of Mars are examined, such as the reasons for exploring Mars, mission scenarios, a transportation system for routine visits, technologies for Mars expeditions, the human factors for Mars missions, life support systems, living and working on Mars, and the report of the National Commission on Space

Gradient descent for robust kernel-based regression

Science.gov (United States)

Guo, Zheng-Chu; Hu, Ting; Shi, Lei

2018-06-01

In this paper, we study the gradient descent algorithm generated by a robust loss function over a reproducing kernel Hilbert space (RKHS). The loss function is defined by a windowing function G and a scale parameter σ, which can include a wide range of commonly used robust losses for regression. There is still a gap between theoretical analysis and optimization process of empirical risk minimization based on loss: the estimator needs to be global optimal in the theoretical analysis while the optimization method can not ensure the global optimality of its solutions. In this paper, we aim to fill this gap by developing a novel theoretical analysis on the performance of estimators generated by the gradient descent algorithm. We demonstrate that with an appropriately chosen scale parameter σ, the gradient update with early stopping rules can approximate the regression function. Our elegant error analysis can lead to convergence in the standard L 2 norm and the strong RKHS norm, both of which are optimal in the mini-max sense. We show that the scale parameter σ plays an important role in providing robustness as well as fast convergence. The numerical experiments implemented on synthetic examples and real data set also support our theoretical results.

Mars north polar deposits: stratigraphy, age, and geodynamical response.

Science.gov (United States)

Phillips, Roger J; Zuber, Maria T; Smrekar, Suzanne E; Mellon, Michael T; Head, James W; Tanaka, Kenneth L; Putzig, Nathaniel E; Milkovich, Sarah M; Campbell, Bruce A; Plaut, Jeffrey J; Safaeinili, Ali; Seu, Roberto; Biccari, Daniela; Carter, Lynn M; Picardi, Giovanni; Orosei, Roberto; Mohit, P Surdas; Heggy, Essam; Zurek, Richard W; Egan, Anthony F; Giacomoni, Emanuele; Russo, Federica; Cutigni, Marco; Pettinelli, Elena; Holt, John W; Leuschen, Carl J; Marinangeli, Lucia

2008-05-30

The Shallow Radar (SHARAD) on the Mars Reconnaissance Orbiter has imaged the internal stratigraphy of the north polar layered deposits of Mars. Radar reflections within the deposits reveal a laterally continuous deposition of layers, which typically consist of four packets of finely spaced reflectors separated by homogeneous interpacket regions of nearly pure ice. The packet/interpacket structure can be explained by approximately million-year periodicities in Mars' obliquity or orbital eccentricity. The observed approximately 100-meter maximum deflection of the underlying substrate in response to the ice load implies that the present-day thickness of an equilibrium elastic lithosphere is greater than 300 kilometers. Alternatively, the response to the load may be in a transient state controlled by mantle viscosity. Both scenarios probably require that Mars has a subchondritic abundance of heat-producing elements.

Is prenatal urethral descent a risk factor for urinary incontinence during pregnancy and the postpartum period?

Science.gov (United States)

Pizzoferrato, Anne-Cécile; Fauconnier, Arnaud; Bader, Georges; de Tayrac, Renaud; Fort, Julie; Fritel, Xavier

2016-07-01

Obstetric trauma during childbirth is considered a major risk factor for postpartum urinary incontinence (UI), particularly stress urinary incontinence. Our aim was to investigate the relation between postpartum UI, mode of delivery, and urethral descent, and to define a group of women who are particularly at risk of postnatal UI. A total of 186 women were included their first pregnancy. Validated questionnaires about urinary symptoms during pregnancy, 2 and 12 months after delivery, were administered. Urethral descent was assessed clinically and by ultrasound at inclusion. Multivariate logistic regression analysis was used to determine the risk factors for UI during pregnancy, at 2 months and 1 year after first delivery. The prevalence of UI was 38.6, 46.5, 35.6, and 34.4 % at inclusion, late pregnancy, 2 months postpartum, and 1 year postpartum respectively. No significant association was found between UI at late pregnancy and urethral descent assessed clinically or by ultrasound. The only risk factor for UI at 2 months postpartum was UI at inclusion (OR 6.27 [95 % CI 2.70-14.6]). The risk factors for UI at 1 year postpartum were UI at inclusion (6.14 [2.22-16.9]), body mass index (BMI), and urethral descent at inclusion, assessed clinically (7.21 [2.20-23.7]) or by ultrasound. The mode of delivery was not associated with urethral descent. Prenatal urethral descent and UI during pregnancy are risk factors for UI at 1 year postpartum. These results indicate that postnatal UI is more strongly influenced by susceptibility factors existing before first delivery than by the mode of delivery.

The Topography of Mars: Understanding the Surface of Mars Through the Mars Orbiter Laser Altimeter

Science.gov (United States)

Derby, C. A.; Neumann, G. A.; Sakimoto, S. E.

2001-12-01

The Mars Orbiter Laser Altimeter has been orbiting Mars since 1997 and has measured the topography of Mars with a meter of vertical accuracy. This new information has improved our understanding of both the surface and the interior of Mars. The topographic globe and the labeled topographic map of Mars illustrate these new data in a format that can be used in a classroom setting. The map is color shaded to show differences in elevation on Mars, presenting Mars with a different perspective than traditional geological and geographic maps. Through the differences in color, students can see Mars as a three-dimensional surface and will be able to recognize features that are invisible in imagery. The accompanying lesson plans are designed for middle school science students and can be used both to teach information about Mars as a planet and Mars in comparison to Earth, fitting both the solar system unit and the Earth science unit in a middle school curriculum. The lessons are referenced to the National Benchmark standards for students in grades 6-8 and cover topics such as Mars exploration, the Mars Orbiter Laser Altimeter, resolution and powers of 10, gravity, craters, seismic waves and the interior structure of a planet, isostasy, and volcanoes. Each lesson is written in the 5 E format and includes a student content activity and an extension showing current applications of Mars and MOLA data. These activities can be found at http://ltpwww.gsfc.nasa.gov/education/resources.html. Funding for this project was provided by the Maryland Space Grant Consortium and the MOLA Science Team, Goddard Space Flight Center.

Local flow management/profile descent algorithm. Fuel-efficient, time-controlled profiles for the NASA TSRV airplane

Science.gov (United States)

Groce, J. L.; Izumi, K. H.; Markham, C. H.; Schwab, R. W.; Thompson, J. L.

1986-01-01

The Local Flow Management/Profile Descent (LFM/PD) algorithm designed for the NASA Transport System Research Vehicle program is described. The algorithm provides fuel-efficient altitude and airspeed profiles consistent with ATC restrictions in a time-based metering environment over a fixed ground track. The model design constraints include accommodation of both published profile descent procedures and unpublished profile descents, incorporation of fuel efficiency as a flight profile criterion, operation within the performance capabilities of the Boeing 737-100 airplane with JT8D-7 engines, and conformity to standard air traffic navigation and control procedures. Holding and path stretching capabilities are included for long delay situations.

SU-G-IeP2-03: Comparison of Dose Calculation On MAR (metal Artifact Reduction) and Non-MAR Datasets for Pelvic Patients with Hip Prosthesis and Head and Neck Patients with Dental Filling

International Nuclear Information System (INIS)

Huang, V; Kohli, K

2016-01-01

Purpose: Metal artifact reduction (MAR) software in computed tomography (CT) was previously evaluated with phantoms demonstrating the algorithm is capable of reducing metal artifacts without affecting the overall image quality. The goal of this study is to determine the dosimetric impact when calculating with CT datasets reconstructed with and without MAR software. Methods: Twelve head and neck cancer patients with dental fillings and four pelvic cancer patients with hip prosthesis were scanned with a GE Optima RT 580 CT scanner. Images were reconstructed with and without the MAR software. 6MV IMRT and VMAT plans were calculated with AAA on the MAR dataset until all constraints met our clinic’s guidelines. Contours from the MAR dataset were copied to the non-MAR dataset. Next, dose calculation on the non-MAR dataset was performed using the same field arrangements and fluence as the MAR plan. Conformality index, D99% and V100% to PTV were compared between MAR and non-MAR plans. Results: Differences between MAR and non-MAR plans were evaluated. For head and neck plans, the largest variations in conformality index, D99% and V100% were −3.8%, −0.9% and −2.1% respectively whereas for pelvic plans, the biggest discrepancies were −32.7%, −0.4% and -33.5% respectively. The dosimetric impact from hip prosthesis is greater because it produces more artifacts compared to dental fillings. Coverage to PTV can increase or decrease depending on the artifacts since dark streaks reduce the HU whereas bright streaks increase the HU. In the majority of the cases, PTV dose in the non-MAR plans is higher than MAR plans. Conclusion: With the presence of metals, MAR algorithm can allow more accurate delineation of targets and OARs. Dose difference between MAR and non-MAR plans depends on the proximity of the organ to the high density material, the streaking artifacts and the beam arrangements of the plan.

SU-G-IeP2-03: Comparison of Dose Calculation On MAR (metal Artifact Reduction) and Non-MAR Datasets for Pelvic Patients with Hip Prosthesis and Head and Neck Patients with Dental Filling

Energy Technology Data Exchange (ETDEWEB)

Huang, V; Kohli, K [BC Cancer Agency, Surrey, BC (United Kingdom)

2016-06-15

Purpose: Metal artifact reduction (MAR) software in computed tomography (CT) was previously evaluated with phantoms demonstrating the algorithm is capable of reducing metal artifacts without affecting the overall image quality. The goal of this study is to determine the dosimetric impact when calculating with CT datasets reconstructed with and without MAR software. Methods: Twelve head and neck cancer patients with dental fillings and four pelvic cancer patients with hip prosthesis were scanned with a GE Optima RT 580 CT scanner. Images were reconstructed with and without the MAR software. 6MV IMRT and VMAT plans were calculated with AAA on the MAR dataset until all constraints met our clinic’s guidelines. Contours from the MAR dataset were copied to the non-MAR dataset. Next, dose calculation on the non-MAR dataset was performed using the same field arrangements and fluence as the MAR plan. Conformality index, D99% and V100% to PTV were compared between MAR and non-MAR plans. Results: Differences between MAR and non-MAR plans were evaluated. For head and neck plans, the largest variations in conformality index, D99% and V100% were −3.8%, −0.9% and −2.1% respectively whereas for pelvic plans, the biggest discrepancies were −32.7%, −0.4% and -33.5% respectively. The dosimetric impact from hip prosthesis is greater because it produces more artifacts compared to dental fillings. Coverage to PTV can increase or decrease depending on the artifacts since dark streaks reduce the HU whereas bright streaks increase the HU. In the majority of the cases, PTV dose in the non-MAR plans is higher than MAR plans. Conclusion: With the presence of metals, MAR algorithm can allow more accurate delineation of targets and OARs. Dose difference between MAR and non-MAR plans depends on the proximity of the organ to the high density material, the streaking artifacts and the beam arrangements of the plan.

Polygon on Mars

Science.gov (United States)

2008-01-01

This image shows a small-scale polygonal pattern in the ground near NASA's Phoenix Mars Lander. This pattern is similar in appearance to polygonal structures in icy ground in the arctic regions of Earth. Phoenix touched down on the Red Planet at 4:53 p.m. Pacific Time (7:53 p.m. Eastern Time), May 25, 2008, in an arctic region called Vastitas Borealis, at 68 degrees north latitude, 234 degrees east longitude. This image was acquired by the Surface Stereo Imager shortly after landing. On the Phoenix mission calendar, landing day is known as Sol 0, the first Martian day of the mission. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Screening for homozygosity by descent in families with autosomal

Indian Academy of Sciences (India)

Home; Journals; Journal of Genetics; Volume 81; Issue 2 ... Perspectives Volume 81 Issue 2 August 2002 pp 59-63 ... disease locus in families with the recessive form of the disease, we used the approach of screening for homozygosity by descent in offspring of consanguineous and nonconsanguineous families with RP.

Airborne Management of Traffic Conflicts in Descent With Arrival Constraints

Science.gov (United States)

Doble, Nathan A.; Barhydt, Richard; Krishnamurthy, Karthik

2005-01-01

NASA is studying far-term air traffic management concepts that may increase operational efficiency through a redistribution of decisionmaking authority among airborne and ground-based elements of the air transportation system. One component of this research, En Route Free Maneuvering, allows trained pilots of equipped autonomous aircraft to assume responsibility for traffic separation. Ground-based air traffic controllers would continue to separate traffic unequipped for autonomous operations and would issue flow management constraints to all aircraft. To evaluate En Route Free Maneuvering operations, a human-in-the-loop experiment was jointly conducted by the NASA Ames and Langley Research Centers. In this experiment, test subject pilots used desktop flight simulators to resolve conflicts in cruise and descent, and to adhere to air traffic flow constraints issued by test subject controllers. Simulators at NASA Langley were equipped with a prototype Autonomous Operations Planner (AOP) flight deck toolset to assist pilots with conflict management and constraint compliance tasks. Results from the experiment are presented, focusing specifically on operations during the initial descent into the terminal area. Airborne conflict resolution performance in descent, conformance to traffic flow management constraints, and the effects of conflicting traffic on constraint conformance are all presented. Subjective data from subject pilots are also presented, showing perceived levels of workload, safety, and acceptability of autonomous arrival operations. Finally, potential AOP functionality enhancements are discussed along with suggestions to improve arrival procedures.

Ptychographic overlap constraint errors and the limits of their numerical recovery using conjugate gradient descent methods.

Science.gov (United States)

Tripathi, Ashish; McNulty, Ian; Shpyrko, Oleg G

2014-01-27

Ptychographic coherent x-ray diffractive imaging is a form of scanning microscopy that does not require optics to image a sample. A series of scanned coherent diffraction patterns recorded from multiple overlapping illuminated regions on the sample are inverted numerically to retrieve its image. The technique recovers the phase lost by detecting the diffraction patterns by using experimentally known constraints, in this case the measured diffraction intensities and the assumed scan positions on the sample. The spatial resolution of the recovered image of the sample is limited by the angular extent over which the diffraction patterns are recorded and how well these constraints are known. Here, we explore how reconstruction quality degrades with uncertainties in the scan positions. We show experimentally that large errors in the assumed scan positions on the sample can be numerically determined and corrected using conjugate gradient descent methods. We also explore in simulations the limits, based on the signal to noise of the diffraction patterns and amount of overlap between adjacent scan positions, of just how large these errors can be and still be rendered tractable by this method.

Intelligent Data Understanding for Architecture Analysis of Entry, Descent, and Landing

Data.gov (United States)

National Aeronautics and Space Administration — Because Entry, Descent and Landing (EDL) system validations are limited in Earth environments, these technologies rely heavily on models and analysis tools to...

Automatic detection of surface changes on Mars - a status report

Science.gov (United States)

Sidiropoulos, Panagiotis; Muller, Jan-Peter

2016-10-01

Orbiter missions have acquired approximately 500,000 high-resolution visible images of the Martian surface, covering an area approximately 6 times larger than the overall area of Mars. This data abundance allows the scientific community to examine the Martian surface thoroughly and potentially make exciting new discoveries. However, the increased data volume, as well as its complexity, generate problems at the data processing stages, which are mainly related to a number of unresolved issues that batch-mode planetary data processing presents. As a matter of fact, the scientific community is currently struggling to scale the common ("one-at-a-time" processing of incoming products by expert scientists) paradigm to tackle the large volumes of input data. Moreover, expert scientists are more or less forced to use complex software in order to extract input information for their research from raw data, even though they are not data scientists themselves.Our work within the STFC and EU FP7 i-Mars projects aims at developing automated software that will process all of the acquired data, leaving domain expert planetary scientists to focus on their final analysis and interpretation. Moreover, after completing the development of a fully automated pipeline that processes automatically the co-registration of high-resolution NASA images to ESA/DLR HRSC baseline, our main goal has shifted to the automated detection of surface changes on Mars. In particular, we are developing a pipeline that uses as an input multi-instrument image pairs, which are processed by an automated pipeline, in order to identify changes that are correlated with Mars surface dynamic phenomena. The pipeline has currently been tested in anger on 8,000 co-registered images and by the time of DPS/EPSC we expect to have processed many tens of thousands of image pairs, producing a set of change detection results, a subset of which will be shown in the presentation.The research leading to these results has received

Impact of metal artifact reduction software on image quality of gemstone spectral imaging dual-energy cerebral CT angiography after intracranial aneurysm clipping

Energy Technology Data Exchange (ETDEWEB)

Dunet, Vincent; Bernasconi, Martine; Hajdu, Steven David; Meuli, Reto Antoine; Zerlauth, Jean-Baptiste [Lausanne University Hospital, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland); Daniel, Roy Thomas [Lausanne University Hospital, Department of Neurosurgery, Lausanne (Switzerland)

2017-09-15

We aimed to assess the impact of metal artifact reduction software (MARs) on image quality of gemstone spectral imaging (GSI) dual-energy (DE) cerebral CT angiography (CTA) after intracranial aneurysm clipping. This retrospective study was approved by the institutional review board, which waived patient written consent. From January 2013 to September 2016, single source DE cerebral CTA were performed in 45 patients (mean age: 60 ± 9 years, male 9) after intracranial aneurysm clipping and reconstructed with and without MARs. Signal-to-noise (SNR), contrast-to-noise (CNR), and relative CNR (rCNR) ratios were calculated from attenuation values measured in the internal carotid artery (ICA) and middle cerebral artery (MCA). Volume of clip and artifacts and relative clip blurring reduction (rCBR) ratios were also measured at each energy level with/without MARs. Variables were compared between GSI and GSI-MARs using the paired Wilcoxon signed-rank test. MARs significantly reduced metal artifacts at all energy levels but 130 and 140 keV, regardless of clips' location and number. The optimal rCBR was obtained at 110 and 80 keV, respectively, on GSI and GSI-MARs images, with up to 96% rCNR increase on GSI-MARs images. The best compromise between metal artifact reduction and rCNR was obtained at 70-75 and 65-70 keV for GSI and GSI-MARs images, respectively, with up to 15% rCBR and rCNR increase on GSI-MARs images. MARs significantly reduces metal artifacts on DE cerebral CTA after intracranial aneurysm clipping regardless of clips' location and number. It may be used to reduce radiation dose while increasing CNR. (orig.)

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.

Thermophysical properties of the MER and Beagle II landing site regions on Mars

Science.gov (United States)

Jakosky, Bruce M.; Hynek, Brian M.; Pelkey, Shannon M.; Mellon, Michael T.; Martínez-Alonso, Sara; Putzig, Nathaniel E.; Murphy, Nate; Christensen, Philip R.

2006-08-01

We analyzed remote-sensing observations of the Isidis Basin, Gusev Crater, and Meridiani Planum landing sites for Beagle II, MER-A Spirit, and MER-B Opportunity spacecraft, respectively. We emphasized the thermophysical properties using daytime and nighttime radiance measurements from the Mars Global Surveyor (MGS) Thermal Emission Spectrometer and Mars Odyssey Thermal Emission Imaging System (THEMIS) and thermal inertias derived from nighttime data sets. THEMIS visible images, MGS Mars Orbiter Camera (MOC) narrow-angle images, and MGS Mars Orbiter Laser Altimeter (MOLA) data are incorporated as well. Additionally, the remote-sensing data were compared with ground-truth at the MER sites. The Isidis Basin surface layer has been shaped by aeolian processes and erosion by slope winds coming off of the southern highlands and funneling through notches between massifs. In the Gusev region, surface materials of contrasting thermophysical properties have been interpreted as rocks or bedrock, duricrust, and dust deposits; these are consistent with a complex geological history dominated by volcanic and aeolian processes. At Meridiani Planum the many layers having different thermophysical and erosional properties suggest periodic deposition of differing sedimentological facies possibly related to clast size, grain orientation and packing, or mineralogy.

Edge-preserving image denoising via group coordinate descent on the GPU.

Science.gov (United States)

McGaffin, Madison Gray; Fessler, Jeffrey A

2015-04-01

Image denoising is a fundamental operation in image processing, and its applications range from the direct (photographic enhancement) to the technical (as a subproblem in image reconstruction algorithms). In many applications, the number of pixels has continued to grow, while the serial execution speed of computational hardware has begun to stall. New image processing algorithms must exploit the power offered by massively parallel architectures like graphics processing units (GPUs). This paper describes a family of image denoising algorithms well-suited to the GPU. The algorithms iteratively perform a set of independent, parallel 1D pixel-update subproblems. To match GPU memory limitations, they perform these pixel updates in-place and only store the noisy data, denoised image, and problem parameters. The algorithms can handle a wide range of edge-preserving roughness penalties, including differentiable convex penalties and anisotropic total variation. Both algorithms use the majorize-minimize framework to solve the 1D pixel update subproblem. Results from a large 2D image denoising problem and a 3D medical imaging denoising problem demonstrate that the proposed algorithms converge rapidly in terms of both iteration and run-time.

The High Resolution Stereo Camera (HRSC) of Mars Express and its approach to science analysis and mapping for Mars and its satellites

Science.gov (United States)

Gwinner, K.; Jaumann, R.; Hauber, E.; Hoffmann, H.; Heipke, C.; Oberst, J.; Neukum, G.; Ansan, V.; Bostelmann, J.; Dumke, A.; Elgner, S.; Erkeling, G.; Fueten, F.; Hiesinger, H.; Hoekzema, N. M.; Kersten, E.; Loizeau, D.; Matz, K.-D.; McGuire, P. C.; Mertens, V.; Michael, G.; Pasewaldt, A.; Pinet, P.; Preusker, F.; Reiss, D.; Roatsch, T.; Schmidt, R.; Scholten, F.; Spiegel, M.; Stesky, R.; Tirsch, D.; van Gasselt, S.; Walter, S.; Wählisch, M.; Willner, K.

2016-07-01

The High Resolution Stereo Camera (HRSC) of ESA's Mars Express is designed to map and investigate the topography of Mars. The camera, in particular its Super Resolution Channel (SRC), also obtains images of Phobos and Deimos on a regular basis. As HRSC is a push broom scanning instrument with nine CCD line detectors mounted in parallel, its unique feature is the ability to obtain along-track stereo images and four colors during a single orbital pass. The sub-pixel accuracy of 3D points derived from stereo analysis allows producing DTMs with grid size of up to 50 m and height accuracy on the order of one image ground pixel and better, as well as corresponding orthoimages. Such data products have been produced systematically for approximately 40% of the surface of Mars so far, while global shape models and a near-global orthoimage mosaic could be produced for Phobos. HRSC is also unique because it bridges between laser altimetry and topography data derived from other stereo imaging instruments, and provides geodetic reference data and geological context to a variety of non-stereo datasets. This paper, in addition to an overview of the status and evolution of the experiment, provides a review of relevant methods applied for 3D reconstruction and mapping, and respective achievements. We will also review the methodology of specific approaches to science analysis based on joint analysis of DTM and orthoimage information, or benefitting from high accuracy of co-registration between multiple datasets, such as studies using multi-temporal or multi-angular observations, from the fields of geomorphology, structural geology, compositional mapping, and atmospheric science. Related exemplary results from analysis of HRSC data will be discussed. After 10 years of operation, HRSC covered about 70% of the surface by panchromatic images at 10-20 m/pixel, and about 97% at better than 100 m/pixel. As the areas with contiguous coverage by stereo data are increasingly abundant, we also

Edge-preserving image denoising via group coordinate descent on the GPU

OpenAIRE

McGaffin, Madison G.; Fessler, Jeffrey A.

2015-01-01

Image denoising is a fundamental operation in image processing, and its applications range from the direct (photographic enhancement) to the technical (as a subproblem in image reconstruction algorithms). In many applications, the number of pixels has continued to grow, while the serial execution speed of computational hardware has begun to stall. New image processing algorithms must exploit the power offered by massively parallel architectures like graphics processing units (GPUs). This pape...

The Role of la Familia for Women of Mexican Descent Who Are Leaders in Higher Education

Science.gov (United States)

Elizondo, Sandra Gray

2012-01-01

The purpose of this qualitative case study was to describe the role of "la familia" for women of Mexican descent as it relates to their development as leaders and their leadership in academia. Purposeful sampling was utilized to reach the goal of 18 participants who were female academic leaders of Mexican descent teaching full time in…

Thermophysical Properties of Mars' North Polar Layered Deposits and Related Materials from Mars Odyssey THEMIS

Science.gov (United States)

Vasavada, A. R.; Richardson, M. I.; Byrne, S.; Ivanov, A. B.; Christensen, P. R.

2003-01-01

The presence of a thick sequence of horizontal layers of ice-rich material at Mars north pole, dissected by troughs and eroding at its margins, is undoubtedly telling us something about the evolution of Mars climate [1,2] we just don t know what yet. The North Polar Layered Deposits (NPLD) most likely formed as astronomically driven climate variations led to the deposition of conformable, areally extensive layers of ice and dust over the polar region. More recently, the balance seems to have fundamentally shifted to net erosion, as evidenced by the many troughs within the NPLD and the steep, arcuate scarps present near its margins, both of which expose layering. We defined a number of Regions of Interest ROI) for THEMIS to target as part of the Mars Odyssey Participating Scientist program. We use these THEMIS data in order to understand the morphology and color/thermal properties of the NPLD and related materials over relevant (i.e., m to km) spatial scales. We have assembled color mosaics of our ROIs in order to map the distribution of ices, the different layered units, dark material, and underlying basement. The color information from THEMIS is crucial for distinguishing these different units which are less distinct on Mars Orbiter Camera images. We wish to understand the nature of the marginal scarps and their relationship to the dark material. Our next, more ambitious goal is to derive the thermophysical properties of the different geologic materials using THEMIS and Mars Global Surveyor Thermal Emission Spectrometer TES) data.

TMBM: Tethered Micro-Balloons on Mars

Science.gov (United States)

Sims, M. H.; Greeley, R.; Cutts, J. A.; Yavrouian, A. H.; Murbach, M.

2000-01-01

The use of balloons/aerobots on Mars has been under consideration for many years. Concepts include deployment during entry into the atmosphere from a carrier spacecraft, deployment from a lander, use of super-pressurized systems for long duration flights, 'hot-air' systems, etc. Principal advantages include the ability to obtain high-resolution data of the surface because balloons provide a low-altitude platform which moves relatively slowly. Work conducted within the last few years has removed many of the technical difficulties encountered in deployment and operation of balloons/aerobots on Mars. The concept proposed here (a tethered balloon released from a lander) uses a relatively simple approach which would enable aspects of Martian balloons to be tested while providing useful and potentially unique science results. Tethered Micro-Balloons on Mars (TMBM) would be carried to Mars on board a future lander as a stand-alone experiment having a total mass of one to two kilograms. It would consist of a helium balloon of up to 50 cubic meters that is inflated after landing and initially tethered to the lander. Its primary instrumentation would be a camera that would be carried to an altitude of up to tens of meters above the surface. Imaging data would be transmitted to the lander for inclusion in the mission data stream. The tether would be released in stages allowing different resolutions and coverage. In addition during this staged release a lander camera system may observe the motion of the balloon at various heights above he lander. Under some scenarios upon completion of the primary phase of TMBM operations, the tether would be cut, allowing TMBM to drift away from the landing site, during which images would be taken along the ground.

"Some curious drawings". Mars through Giovanni Schiaparelli's eyes: between science and fiction.

Science.gov (United States)

Canadelli, Elena

2009-01-01

From the second half of the 19th century up to the first part of the 20th century the drawings of Mars by the Italian astronomer Giovanni Schiaparelli became the centre of an international controversy concerning the existence of canals and the hypothetical habitability of the red planet. These images also generated a full impact on the popular culture of the time. This essays follows the scientific representations of Mars by Schiaparelli (drawings of discs and maps) from their birth in the hands of the astronomy community up to their growing old in the hands of scientific popularizers such as Camille Flammarion and science fiction writers such as Herbert George Wells. With its seas and canyons Mars turned into the ideal background for scientific and exotic romanticism, offering a suitable setting for novels and tales. The core question crossed paths with the contemporary early 20th century debate raging on about the evolutionary theory. The study of Mars moved from astronomy to extraterrestrial physiology, biology, meteorology and geography: astronomical images then became imaginary portraits of Martians and artificial Martian landscapes.

Steepest descent moment method for three-dimensional magnetohydrodynamic equilibria

International Nuclear Information System (INIS)

Hirshman, S.P.; Whitson, J.C.

1983-11-01

An energy principle is used to obtain the solution of the magnetohydrodynamic (MHD) equilibrium equation J Vector x B Vector - del p = 0 for nested magnetic flux surfaces that are expressed in the inverse coordinate representation x Vector = x Vector(rho, theta, zeta). Here, theta and zeta are poloidal and toroidal flux coordinate angles, respectively, and p = p(rho) labels a magnetic surface. Ordinary differential equations in rho are obtained for the Fourier amplitudes (moments) in the doubly periodic spectral decomposition of x Vector. A steepest descent iteration is developed for efficiently solving these nonlinear, coupled moment equations. The existence of a positive-definite energy functional guarantees the monotonic convergence of this iteration toward an equilibrium solution (in the absence of magnetic island formation). A renormalization parameter lambda is introduced to ensure the rapid convergence of the Fourier series for x Vector, while simultaneously satisfying the MHD requirement that magnetic field lines are straight in flux coordinates. A descent iteration is also developed for determining the self-consistent value for lambda

Arachnid aloft: directed aerial descent in neotropical canopy spiders.

Science.gov (United States)

Yanoviak, Stephen P; Munk, Yonatan; Dudley, Robert

2015-09-06

The behaviour of directed aerial descent has been described for numerous taxa of wingless hexapods as they fall from the tropical rainforest canopy, but is not known in other terrestrial arthropods. Here, we describe similar controlled aerial behaviours for large arboreal spiders in the genus Selenops (Selenopidae). We dropped 59 such spiders from either canopy platforms or tree crowns in Panama and Peru; the majority (93%) directed their aerial trajectories towards and then landed upon nearby tree trunks. Following initial dorsoventral righting when necessary, falling spiders oriented themselves and then translated head-first towards targets; directional changes were correlated with bilaterally asymmetric motions of the anterolaterally extended forelegs. Aerial performance (i.e. the glide index) decreased with increasing body mass and wing loading, but not with projected surface area of the spider. Along with the occurrence of directed aerial descent in ants, jumping bristletails, and other wingless hexapods, this discovery of targeted gliding in selenopid spiders further indicates strong selective pressures against uncontrolled falls into the understory for arboreal taxa. © 2015 The Author(s).

Communications During Critical Mission Operations: Preparing for InSight's Landing on Mars

Science.gov (United States)

Asmar, Sami; Oudrhiri, Kamal; Kurtik, Susan; Weinstein-Weiss, Stacy

2014-01-01

Radio communications with deep space missions are often taken for granted due to the impressively successful records since, for decades, the technology and infrastructure have been developed for ground and flight systems to optimize telemetry and commanding. During mission-critical events such as the entry, descent, and landing of a spacecraft on the surface of Mars, the signal's level and frequency dynamics vary significantly and typically exceed the threshold of the budgeted links. The challenge is increased when spacecraft shed antennas with heat shields and other hardware during those risky few minutes. We have in the past successfully received signals on Earth during critical events even ones not intended for ground reception. These included the UHF signal transmitted by Curiosity to Marsorbiting assets. Since NASA's Deep Space Network does not operate in the UHF band, large radio telescopes around the world are utilized. The Australian CSIRO Parkes Radio Telescope supported the Curiosity UHF signal reception and DSN receivers, tools, and expertise were used in the process. In preparation for the InSight mission's landing on Mars in 2016, preparations are underway to support the UHF communications. This paper presents communication scenarios with radio telescopes, and the DSN receiver and tools. It also discusses the usefulness of the real-time information content for better response time by the mission team towards successful mission operations.

Mars: Stratigraphy of Western Highlands and Polar Regions

Science.gov (United States)

Tanaka, K. L.; Scott, D. H.; Tuesink, M. F.

1985-01-01

Geologic mapping and stratigraphic studies of Mars based on Viking images improved knowledge of the relative age and occurrence of geologic units on a global scale. Densities of geologic units or features during the Noarchian, Hesperian, and Amazonian periods are indicated for the North and South polar regions as well as the equatorial region of Mars. Cumulative counts of crater size frequencies for craters larger than 2 km in diameter on plateau units mapped in the western region of Mars counts indicate that the plateau terrain as a whole was thinly resurfaced during the Hesperian Period, and a large proportion of pre-existing craters less than 10 to 15 km in diameter was buried. The formation of northern plains, subpolar highlands, and both polar regions is also described.

Neuromuscular function during stair descent in meniscectomized patients and controls

DEFF Research Database (Denmark)

Thorlund, Jonas Bloch; Roos, Ewa M; Aagaard, Per

2011-01-01

The aim of this study was to identify differences in knee range of motion (ROM), movement speed, ground reaction forces (GRF) profile, neuromuscular activity, and muscle coactivation during the transition between stair descent and level walking in meniscectomized patients at high risk of knee...

Experimental studies of the rotor flow downwash on the Stability of multi-rotor crafts in descent

Science.gov (United States)

Veismann, Marcel; Dougherty, Christopher; Gharib, Morteza

2017-11-01

All rotorcrafts, including helicopters and multicopters, have the inherent problem of entering rotor downwash during vertical descent. As a result, the craft is subject to highly unsteady flow, called vortex ring state (VRS), which leads to a loss of lift and reduced stability. To date, experimental efforts to investigate this phenomenon have been largely limited to analysis of a single, fixed rotor mounted in a horizontal wind tunnel. Our current work aims to understand the interaction of multiple rotors in vertical descent by mounting a multi-rotor craft in a low speed, vertical wind tunnel. Experiments were performed with a fixed and rotationally free mounting; the latter allowing us to better capture the dynamics of a free flying drone. The effect of rotor separation on stability, generated thrust, and rotor wake interaction was characterized using force gauge data and PIV analysis for various descent velocities. The results obtained help us better understand fluid-craft interactions of drones in vertical descent and identify possible sources of instability. The presented material is based upon work supported by the Center for Autonomous Systems and Technologies (CAST) at the Graduate Aerospace Laboratories of the California Institute of Technology (GALCIT).

Secular Climate Change on Mars: An Update Using MSL Pressure Data

Science.gov (United States)

Haberle, R. M.; Gomez-Elvira, J.; Juarez, M. de la Torre; Harri, A.-M.; Hollingsworth, J. L.; Kahanpaa, H.; Kahre, M. A.; Lemmon, M.; Martin-Torres, F. J.; Mischna, M.;

Seasonal Transport in Mars' Mesosphere-Thermosphere revealed by Nitric Oxide nightglow

Science.gov (United States)

Royer, E. M.; Stiepen, A.; Schneider, N. M.; Jain, S.; Milby, Z.; Deighan, J.; Gonzalez-Galindo, F.; Bougher, S. W.; Gerard, J. C. M. C.; Stevens, M. H.; Evans, J. S.; Stewart, I. F.; Chaffin, M.; McClintock, B.; Clarke, J. T.; Montmessin, F.; Holsclaw, G.; Lefèvre, F.; Forget, F.; Lo, D.; Hubert, B. A.; Jakosky, B. M.

2017-12-01

We analyze the ultraviolet nightglow in the atmosphere of Mars through the Nitric Oxide (NO) δ and γ band emissions observed by the Imaging Ultraviolet Spectrograph (IUVS, McClintock et al., 2015) when the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft is at apoapsis and periapsis. On the dayside thermosphere of Mars, solar extreme ultraviolet radiation dissociates CO2 and N2 molecules. O(3P) and N(4S) atoms are carried by the day-to-night hemispheric transport. They descend in the nightside mesosphere, where they can radiatively recombine to form NO(C2Π). The excited molecules rapidly relax by emitting UV photons in the δ and γ bands. These emissions are thus indicators of the N and O atom fluxes transported from the dayside to Mars' nightside and the descending circulation pattern from the nightside thermosphere to the mesosphere (e.g. Bertaux et al., 2005 ; Bougher et al., 1990 ; Cox et al., 2008 ; Gagné et al., 2013 ; Gérard et al., 2008 ; Stiepen et al., 2015, 2017). A large dataset of nightside disk images and vertical limb scans during southern winter, fall equinox and southern summer conditions have been accumulated since the beginning of the mission. We will present a discussion regarding the variability of the brightness and altitude of the emission with season, geographical position (longitude) and local time and possible interpretation for local and global changes in the mesosphere dynamics. We show the possible impact of atmospheric waves structuring the emission longitudinally and indicating a wave-3 structure in Mars' nightside mesosphere. Quantitative comparison with calculations from the LMD-MGCM (Laboratoire de Météorologie Dynamique-Mars Global Climate Model) show that the model globally reproduces the trends of the NO nightglow emission and its seasonal variation but also indicates large discrepancies (up to a factor 50 fainter in the model) suggesting that the predicted transport is too efficient toward the night winter pole

Soft Rock Yields Clues to Mars' Past

Science.gov (United States)

2004-01-01

[figure removed for brevity, see original site] Figure 1 This image taken by the Mars Exploration Rover Spirit shows the rock outcrop dubbed 'Clovis.' The rock was discovered to be softer than other rocks studied so far at Gusev Crater after the rover easily ground a hole into it with its rock abrasion tool. Spirit's solar panels can be seen in the foreground. This image was taken by the rover's navigation camera on sol 205 (July 31, 2004). Elemental Trio Found in 'Clovis' Figure 1 above shows that the interior of the rock dubbed 'Clovis' contains higher concentrations of sulfur, bromine and chlorine than basaltic, or volcanic, rocks studied so far at Gusev Crater. The data were taken by the Mars Exploration Rover Spirit's alpha particle X-ray spectrometer after the rover dug into Clovis with its rock abrasion tool. The findings might indicate that this rock was chemically altered, and that fluids once flowed through the rock depositing these elements.

Stereotypes of women of Asian descent in midwifery: some evidence.

Science.gov (United States)

Bowler, I M

1993-03-01

The subject of this paper is part of a larger study which investigated the delivery of maternity care to women of South Asian descent in Britain (Bowler, 1990). An ethnographic approach was used and the main method of data collection was non-participant observation in antenatal clinics, labour and postnatal wards in a teaching hospital maternity unit. These observations were supported by data from interviews with midwives. It was found that the midwives commonly use stereotypes of women in order to help them to provide care. These stereotypes are particularly likely to be used in situations where the midwife has difficulty (through pressure of time or other circumstances) in getting to know an individual woman. The stereotype of women of Asian descent contained four main themes: communication problems; failure to comply with care and service abuse; making a fuss about nothing; a lack of normal maternal instinct. Reasons for stereotyping are explored. Effects on service provision in the areas of family planning and breast feeding are highlighted.

Minimum-fuel turning climbout and descent guidance of transport jets

Science.gov (United States)

Neuman, F.; Kreindler, E.

1983-01-01

The complete flightpath optimization problem for minimum fuel consumption from takeoff to landing including the initial and final turns from and to the runway heading is solved. However, only the initial and final segments which contain the turns are treated, since the straight-line climbout, cruise, and descent problems have already been solved. The paths are derived by generating fields of extremals, using the necessary conditions of optimal control together with singular arcs and state constraints. Results show that the speed profiles for straight flight and turning flight are essentially identical except for the final horizontal accelerating or decelerating turns. The optimal turns require no abrupt maneuvers, and an approximation of the optimal turns could be easily integrated with present straight-line climb-cruise-descent fuel-optimization algorithms. Climbout at the optimal IAS rather than the 250-knot terminal-area speed limit would save 36 lb of fuel for the 727-100 aircraft.

Dosimetric Evaluation of Metal Artefact Reduction using Metal Artefact Reduction (MAR) Algorithm and Dual-energy Computed Tomography (CT) Method

Science.gov (United States)

Laguda, Edcer Jerecho

Purpose: Computed Tomography (CT) is one of the standard diagnostic imaging modalities for the evaluation of a patient's medical condition. In comparison to other imaging modalities such as Magnetic Resonance Imaging (MRI), CT is a fast acquisition imaging device with higher spatial resolution and higher contrast-to-noise ratio (CNR) for bony structures. CT images are presented through a gray scale of independent values in Hounsfield units (HU). High HU-valued materials represent higher density. High density materials, such as metal, tend to erroneously increase the HU values around it due to reconstruction software limitations. This problem of increased HU values due to metal presence is referred to as metal artefacts. Hip prostheses, dental fillings, aneurysm clips, and spinal clips are a few examples of metal objects that are of clinical relevance. These implants create artefacts such as beam hardening and photon starvation that distort CT images and degrade image quality. This is of great significance because the distortions may cause improper evaluation of images and inaccurate dose calculation in the treatment planning system. Different algorithms are being developed to reduce these artefacts for better image quality for both diagnostic and therapeutic purposes. However, very limited information is available about the effect of artefact correction on dose calculation accuracy. This research study evaluates the dosimetric effect of metal artefact reduction algorithms on severe artefacts on CT images. This study uses Gemstone Spectral Imaging (GSI)-based MAR algorithm, projection-based Metal Artefact Reduction (MAR) algorithm, and the Dual-Energy method. Materials and Methods: The Gemstone Spectral Imaging (GSI)-based and SMART Metal Artefact Reduction (MAR) algorithms are metal artefact reduction protocols embedded in two different CT scanner models by General Electric (GE), and the Dual-Energy Imaging Method was developed at Duke University. All three

Planetary Data Systems (PDS) Imaging Node Atlas II

Science.gov (United States)

Stanboli, Alice; McAuley, James M.

2013-01-01

The Planetary Image Atlas (PIA) is a Rich Internet Application (RIA) that serves planetary imaging data to the science community and the general public. PIA also utilizes the USGS Unified Planetary Coordinate system (UPC) and the on-Mars map server. The Atlas was designed to provide the ability to search and filter through greater than 8 million planetary image files. This software is a three-tier Web application that contains a search engine backend (MySQL, JAVA), Web service interface (SOAP) between server and client, and a GWT Google Maps API client front end. This application allows for the search, retrieval, and download of planetary images and associated meta-data from the following missions: 2001 Mars Odyssey, Cassini, Galileo, LCROSS, Lunar Reconnaissance Orbiter, Mars Exploration Rover, Mars Express, Magellan, Mars Global Surveyor, Mars Pathfinder, Mars Reconnaissance Orbiter, MESSENGER, Phoe nix, Viking Lander, Viking Orbiter, and Voyager. The Atlas utilizes the UPC to translate mission-specific coordinate systems into a unified coordinate system, allowing the end user to query across missions of similar targets. If desired, the end user can also use a mission-specific view of the Atlas. The mission-specific views rely on the same code base. This application is a major improvement over the initial version of the Planetary Image Atlas. It is a multi-mission search engine. This tool includes both basic and advanced search capabilities, providing a product search tool to interrogate the collection of planetary images. This tool lets the end user query information about each image, and ignores the data that the user has no interest in. Users can reduce the number of images to look at by defining an area of interest with latitude and longitude ranges.

PRISMA-MAR: An Architecture Model for Data Visualization in Augmented Reality Mobile Devices

Science.gov (United States)

Gomes Costa, Mauro Alexandre Folha; Serique Meiguins, Bianchi; Carneiro, Nikolas S.; Gonçalves Meiguins, Aruanda Simões

2013-01-01

This paper proposes an extension to mobile augmented reality (MAR) environments--the addition of data charts to the more usual text, image and video components. To this purpose, we have designed a client-server architecture including the main necessary modules and services to provide an Information Visualization MAR experience. The server side…

Machado-Joseph disease in pedigrees of Azorean descent is linked to chromosome 14.

Science.gov (United States)

St George-Hyslop, P; Rogaeva, E; Huterer, J; Tsuda, T; Santos, J; Haines, J L; Schlumpf, K; Rogaev, E I; Liang, Y; McLachlan, D R

1994-07-01

A locus for Machado-Joseph disease (MJD) has recently been mapped to a 30-cM region of chromosome 14q in five pedigrees of Japanese descent. MJD is a clinically pleomorphic neurodegenerative disease that was originally described in subjects of Azorean descent. In light of the nonallelic heterogeneity in other inherited spinocerebellar ataxias, we were interested to determine if the MJD phenotype in Japanese and Azorean pedigrees arose from mutations at the same locus. We provide evidence that MJD in five pedigrees of Azorean descent is also linked to chromosome 14q in an 18-cM region between the markers D14S67 and AACT (multipoint lod score +7.00 near D14S81). We also report molecular evidence for homozygosity at the MJD locus in an MJD-affected subject with severe, early-onset symptoms. These observations confirm the initial report of linkage of MJD to chromosome 14; suggest that MJD in Japanese and Azorean subjects may represent allelic or identical mutations at the same locus; and provide one possible explanation (MJD gene dosage) for the observed phenotypic heterogeneity in this disease.

The Phoenix Mars Lander Robotic Arm

Science.gov (United States)

Bonitz, Robert; Shiraishi, Lori; Robinson, Matthew; Carsten, Joseph; Volpe, Richard; Trebi-Ollennu, Ashitey; Arvidson, Raymond E.; Chu, P. C.; Wilson, J. J.; Davis, K. R.

2009-01-01

The Phoenix Mars Lander Robotic Arm (RA) has operated for over 150 sols since the Lander touched down on the north polar region of Mars on May 25, 2008. During its mission it has dug numerous trenches in the Martian regolith, acquired samples of Martian dry and icy soil, and delivered them to the Thermal Evolved Gas Analyzer (TEGA) and the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA). The RA inserted the Thermal and Electrical Conductivity Probe (TECP) into the Martian regolith and positioned it at various heights above the surface for relative humidity measurements. The RA was used to point the Robotic Arm Camera to take images of the surface, trenches, samples within the scoop, and other objects of scientific interest within its workspace. Data from the RA sensors during trenching, scraping, and trench cave-in experiments have been used to infer mechanical properties of the Martian soil. This paper describes the design and operations of the RA as a critical component of the Phoenix Mars Lander necessary to achieve the scientific goals of the mission.

Additive preservers of the ascent, descent and related subsets

Czech Academy of Sciences Publication Activity Database

Mbekhta, M.; Müller, Vladimír; Oudghiri, M.

2014-01-01

Roč. 71, č. 1 (2014), s. 63-83 ISSN 0379-4024 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional support: RVO:67985840 Keywords : additive preservers * ascent * descent Subject RIV: BA - General Mathematics Impact factor: 0.550, year: 2014 http://www.mathjournals.org/jot/2014-071-001/2014-071-001-004.html

My Changing Perception of Mars: A Whipple Award Lecture

Science.gov (United States)

Malin, M. C.

2017-12-01

I have been studying Mars for 46+ years. My initial studies of the planet were mentored by Bruce Murray (my Ph.D. advisor) and Bob Sharp. My 4 years as Bruce's student were the most productive and exciting of my early career, during which I wrote or participated in a dozen published works. My early efforts on Mars, based on Mariner 9 images, culminated in my Ph.D. dissertation, the last paragraph of which, written in 1975, read: "In summary, Mars appears to have had a complex early history, complete with significant atmospheric and some fluid erosion. Just as the polar layered deposits are believed to record the recent history of Mars, so may the ancient layered deposits — the intercrater plains — record the most primitive history of Mars. Detailed studies of Martian stratigraphy in the distant future may be as intellectually rewarding as the studies of terrestrial stratigraphy are today."Welcome to the distant future! During my student years with Murray and Sharp, I concluded that images of significantly higher spatial resolution were needed to unravel the geologic story hinted at in the Mariner 9 data. For 10 years I made the case for aerial photo-like high resolution imaging, to highly skeptical science and engineering communities. With Ed Danielson (of JPL and then Caltech) and a group of young engineers he recruited, we succeeded in convincing advisory groups and a NASA selection board to fly the Mars Observer Camera, that included early 1980's innovations such as a 32-bit microprocessor, a 100 MB solid state memory, gate arrays for instrument control, and a 35 cm aperture telescope with an f/2 primary and a secondary mirror with 8-fold magnification to achieve 3.7 µrad/pixel scale (1.4 m/pxl from 378 km altitude). Although MO failed, the MOC was reflown on MGS and my colleague Ken Edgett and I found evidence for: widespread water-lain sedimentary rock, persistent surficial water flow and ponding in bodies of standing water, gullies that may indicate the

Mars bevares

DEFF Research Database (Denmark)

Hendricks, Vincent Fella; Hendricks, Elbert

2009-01-01

2009 er femåret for Mission Mars. I den anledning opridser de to kronikører, far og søn, hvorfor man bør lade planer om en bemandet tur til Mars forblive i skrivebordsskuffen......2009 er femåret for Mission Mars. I den anledning opridser de to kronikører, far og søn, hvorfor man bør lade planer om en bemandet tur til Mars forblive i skrivebordsskuffen...

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

The Mars Surveyor missions that will be launched in April of 2001 will include a highly capable rover that is a successor to the Mars Pathfinder mission's Sojourner rover. The design goals for this rover are a total traverse distance of at least 10 km and a total lifetime of at least one Earth year. The rover's job will be to explore a site in Mars' ancient terrain, searching for materials likely to preserve a record of ancient martian water, climate, and possibly biology. The rover will collect rock and soil samples, and will store them for return to Earth by a subsequent Mars Surveyor mission in 2005. The Athena Mars rover science payload is the suite of scientific instruments and sample collection tools that will be used to perform this job. The specific science objectives that NASA has identified for the '01 rover payload are 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. (3) Determine the fine-scale textural properties of these materials. (4) Collect and store samples. The Athena payload has been designed to meet these objectives. The focus of the design is on field operations: making sure the rover can locate, characterize, and collect scientifically important samples in a dusty, dirty, real-world environment. The topography, morphology, and mineralogy of the scene around the rover will be revealed by Pancam/Mini-TES, an integrated imager and IR spectrometer. Pancam views the surface around the rover in stereo and color. It uses two high-resolution cameras that are identical in most respects to the rover's navigation cameras. The detectors are low-power, low-mass active pixel sensors with on-chip 12-bit analog-to-digital conversion. Filters provide 8-12 color spectral bandpasses over the spectral region from 0.4 to 1.1 micron Narrow-angle optics provide an angular resolution of 0

Crack detection using image processing

International Nuclear Information System (INIS)

Moustafa, M.A.A

2010-01-01

This thesis contains five main subjects in eight chapters and two appendices. The first subject discus Wiener filter for filtering images. In the second subject, we examine using different methods, as Steepest Descent Algorithm (SDA) and the Wavelet Transformation, to detect and filling the cracks, and it's applications in different areas as Nano technology and Bio-technology. In third subject, we attempt to find 3-D images from 1-D or 2-D images using texture mapping with Open Gl under Visual C ++ language programming. The fourth subject consists of the process of using the image warping methods for finding the depth of 2-D images using affine transformation, bilinear transformation, projective mapping, Mosaic warping and similarity transformation. More details about this subject will be discussed below. The fifth subject, the Bezier curves and surface, will be discussed in details. The methods for creating Bezier curves and surface with unknown distribution, using only control points. At the end of our discussion we will obtain the solid form, using the so called NURBS (Non-Uniform Rational B-Spline); which depends on: the degree of freedom, control points, knots, and an evaluation rule; and is defined as a mathematical representation of 3-D geometry that can accurately describe any shape from a simple 2-D line, circle, arc, or curve to the most complex 3-D organic free-form surface or (solid) which depends on finding the Bezier curve and creating family of curves (surface), then filling in between to obtain the solid form. Another representation for this subject is concerned with building 3D geometric models from physical objects using image-based techniques. The advantage of image techniques is that they require no expensive equipment; we use NURBS, subdivision surface and mesh for finding the depth of any image with one still view or 2D image. The quality of filtering depends on the way the data is incorporated into the model. The data should be treated with

Mars Recent Climate Change Workshop

Science.gov (United States)

Haberle, Robert M.; Owen, Sandra J.

2012-11-01

Mars Recent Climate Change Workshop NASA/Ames Research Center May 15-17, 2012 Climate change on Mars has been a subject of great interest to planetary scientists since the 1970's when orbiting spacecraft first discovered fluvial landforms on its ancient surfaces and layered terrains in its polar regions. By far most of the attention has been directed toward understanding how "Early Mars" (i.e., Mars >~3.5 Gya) could have produced environmental conditions favorable for the flow of liquid water on its surface. Unfortunately, in spite of the considerable body of work performed on this subject, no clear consensus has emerged on the nature of the early Martian climate system because of the difficulty in distinguishing between competing ideas given the ambiguities in the available geological, mineralogical, and isotopic records. For several reasons, however, the situation is more tractable for "Recent Mars" (i.e., Mars during past 20 My or so). First, the geologic record is better preserved and evidence for climate change on this time scale has been building since the rejuvenation of the Mars Exploration Program in the late 1990's. The increasing coverage of the planet from orbit and the surface, coupled with accurate measurements of surface topography, increasing spatial resolution of imaging cameras, improved spectral resolution of infrared sensors, and the ability to probe the subsurface with radar, gamma rays, and neutron spectroscopy, has not only improved the characterization of previously known climate features such as polar layered terrains and glacier-related landforms, but has also revealed the existence of many new features related to recent climate change such as polygons, gullies, concentric crater fill, and a latitude dependent mantle. Second, the likely cause of climate change - spin axis/orbital variations - is more pronounced on Mars compared to Earth. Spin axis/orbital variations alter the seasonal and latitudinal distribution of sunlight, which can

Mars, High-Resolution Digital Terrain Model Quadrangles on the Basis of Mars-Express HRSC Data

Science.gov (United States)

Dumke, A.; Spiegel, M.; van Gasselt, S.; Neu, D.; Neukum, G.

2010-05-01

Introduction: Since December 2003, the European Space Agency's (ESA) Mars Express (MEX) orbiter has been investigating Mars. The High Resolution Stereo Camera (HRSC), one of the scientific experiments onboard MEX, is a pushbroom stereo color scanning instrument with nine line detectors, each equipped with 5176 CCD sensor elements [1,2]. One of the goals for MEX HRSC is to cover Mars globally in color and stereoscopically at high-resolution. So far, HRSC has covered half of the surface of Mars at a resolution better than 20 meters per pixel. HRSC data allows to derive high-resolution digital terrain models (DTM), color-orthoimage mosaics and additionally higher-level 3D data products. Past work concentrated on producing regional data mosaics for areas of scientific interest in a single strip and/or bundle block adjustment and deriving DTMs [3]. The next logical step, based on substantially the same procedure, is to systematically expand the derivation of DTMs and orthoimage data to the 140 map quadrangle scheme (Q-DTM). Methods: The division of the Mars surface into 140 quadrangles is briefly described in Greeley and Batson [4] and based upon the standard MC 30 (Mars Chart) system. The quadrangles are named by alpha-numerical labels. The workflow for the determination of new orientation data for the derivation of digital terrain models takes place in two steps. First, for each HRSC orbits covering a quadrangle, new exterior orientation parameters are determined [5,6]. The successfully classified exterior orientation parameters become the input for the next step in which the exterior orientation parameters are determined together in a bundle block adjustment. Only those orbit strips which have a sufficient overlap area and a certain number of tie points can be used in a common bundle block adjustment. For the automated determination of tie points, software provided by the Leibniz Universität Hannover [7] is used. Results: For the derivation of Q-DTMs and ortho-image

Peeling Back the Layers of Mars

Science.gov (United States)

2004-01-01

This is a 3-D model of the trench excavated by the Mars Exploration Rover Opportunity on the 23rd day, or sol, of its mission. An oblique view of the trench from a bit above and to the right of the rover's right wheel is shown. The model was generated from images acquired by the rover's front hazard-avoidance cameras.

Seven Possible Cave Skylights on Mars

Science.gov (United States)

2007-01-01

[figure removed for brevity, see original site] Figure 1 Seven very dark holes on the north slope of a Martian volcano have been proposed as possible cave skylights, based on day-night temperature patterns suggesting they are openings to subsurface spaces. These six excerpts of images taken in visible-wavelength light by the Thermal Emission Imaging System camera on NASA's Mars Odyssey orbiter show the seven openings. Solar illumination comes from the left in each frame. The volcano is Arsia Mons, at 9 degrees south latitude, 239 degrees east longitude. The features have been given informal names to aid comparative discussion (see figure 1). They range in diameter from about 100 meters (328 feet) to about 225 meters (738 feet). The candidate cave skylights are (A) 'Dena,' (B) 'Chloe,' (C) 'Wendy,' (D) 'Annie,' (E) 'Abby' (left) and 'Nikki,' and (F) 'Jeanne.' Arrows signify north and the direction of illumination. Mars Odyssey is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The orbiter's Thermal Emission Imaging System was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing, Santa Barbara, Calif., and is operated by Arizona State University.

Assessing the ability to derive rates of polar middle-atmospheric descent using trace gas measurements from remote sensors

Science.gov (United States)

Ryan, Niall J.; Kinnison, Douglas E.; Garcia, Rolando R.; Hoffmann, Christoph G.; Palm, Mathias; Raffalski, Uwe; Notholt, Justus

2018-02-01

We investigate the reliability of using trace gas measurements from remote sensing instruments to infer polar atmospheric descent rates during winter within 46-86 km altitude. Using output from the Specified Dynamics Whole Atmosphere Community Climate Model (SD-WACCM) between 2008 and 2014, tendencies of carbon monoxide (CO) volume mixing ratios (VMRs) are used to assess a common assumption of dominant vertical advection of tracers during polar winter. The results show that dynamical processes other than vertical advection are not negligible, meaning that the transport rates derived from trace gas measurements do not represent the mean descent of the atmosphere. The relative importance of vertical advection is lessened, and exceeded by other processes, during periods directly before and after a sudden stratospheric warming, mainly due to an increase in eddy transport. It was also found that CO chemistry cannot be ignored in the mesosphere due to the night-time layer of OH at approximately 80 km altitude. CO VMR profiles from the Kiruna Microwave Radiometer and the Microwave Limb Sounder were compared to SD-WACCM output, and show good agreement on daily and seasonal timescales. SD-WACCM CO profiles are combined with the CO tendencies to estimate errors involved in calculating the mean descent of the atmosphere from remote sensing measurements. The results indicate errors on the same scale as the calculated descent rates, and that the method is prone to a misinterpretation of the direction of air motion. The true rate of atmospheric descent is seen to be masked by processes, other than vertical advection, that affect CO. We suggest an alternative definition of the rate calculated using remote sensing measurements: not as the mean descent of the atmosphere, but as an effective rate of vertical transport for the trace gas under observation.

Mars Express - ESA sets ambitious goals for the first European mission to Mars

Science.gov (United States)

2003-05-01

built by group of scientific institutes from all over Europe, plus Russia, the United States, Japan and China. These instruments are a subsurface sounding radar; a high-resolution camera, several surface and atmospheric spectrometers, a plasma analyzer and a radio science experiment. The high-resolution camera will image the entire planet in full colour, in 3D, at a resolution of up to 2 metres in selected areas. One of the spectrometers will map the mineral composition of the surface with great accuracy. The missing water Data from some of the instruments will be key to finding out what happened with the water which was apparently so abundant in the past. For instance, the radar altimeter will search for subsurface water and ice, down to a depth of a few kilometres. Scientists expect to find a layer of ice or permafrost, and to measure its thickness. Other observations with the spectrometers will determine the amount of water remaining in the atmosphere. They will also tell whether there is a still a full ‘water cycle’ on Mars, for example how water is deposited in the poles and how it evaporates, depending on the seasons. "These data will determine how much water there is left. We have clear evidence for the presence of water in the past, we have seen dry river beds and sedimentary layers, and there is also evidence for water on present-day Mars. But we do not know how much water there is. Mars Express will tell us,” says Chicarro. The search for life The instruments on board Beagle 2 will investigate the geology and the climate of the landing site. But, above all, it will look for signs of life. Contrary to the Viking missions, Mars Express will search for evidence for both present and past life. Scientists are now more aware that a few biological experiments are not enough to search for life - they will combine many different types of tests to help discard contradictory results. To ‘sniff’ out direct evidence of past or present biological activity, Beagle

On the efficiency of a randomized mirror descent algorithm in online optimization problems

Science.gov (United States)

Gasnikov, A. V.; Nesterov, Yu. E.; Spokoiny, V. G.

2015-04-01

A randomized online version of the mirror descent method is proposed. It differs from the existing versions by the randomization method. Randomization is performed at the stage of the projection of a subgradient of the function being optimized onto the unit simplex rather than at the stage of the computation of a subgradient, which is common practice. As a result, a componentwise subgradient descent with a randomly chosen component is obtained, which admits an online interpretation. This observation, for example, has made it possible to uniformly interpret results on weighting expert decisions and propose the most efficient method for searching for an equilibrium in a zero-sum two-person matrix game with sparse matrix.

Automation, robotics, and inflight training for manned Mars missions

Science.gov (United States)

Holt, Alan C.

1986-01-01

The automation, robotics, and inflight training requirements of manned Mars missions will be supported by similar capabilities developed for the space station program. Evolutionary space station onboard training facilities will allow the crewmembers to minimize the amount of training received on the ground by providing extensive onboard access to system and experiment malfunction procedures, maintenance procedures, repair procedures, and associated video sequences. Considerable on-the-job training will also be conducted for space station management, mobile remote manipulator operations, proximity operations with the Orbital Maneuvering Vehicle (and later the Orbit Transfer Vehicle), and telerobotics and mobile robots. A similar approach could be used for manned Mars mission training with significant additions such as high fidelity image generation and simulation systems such as holographic projection systems for Mars landing, ascent, and rendezvous training. In addition, a substantial increase in the use of automation and robotics for hazardous and tedious tasks would be expected for Mars mission. Mobile robots may be used to assist in the assembly, test and checkout of the Mars spacecraft, in the handling of nuclear components and hazardous chemical propellent transfer operations, in major spacecraft repair tasks which might be needed (repair of a micrometeroid penetration, for example), in the construction of a Mars base, and for routine maintenance of the base when unmanned.

Development and test results of a flight management algorithm for fuel conservative descents in a time-based metered traffic environment

Science.gov (United States)

Knox, C. E.; Cannon, D. G.

1980-01-01

A simple flight management descent algorithm designed to improve the accuracy of delivering an airplane in a fuel-conservative manner to a metering fix at a time designated by air traffic control was developed and flight tested. This algorithm provides a three dimensional path with terminal area time constraints (four dimensional) for an airplane to make an idle thrust, clean configured (landing gear up, flaps zero, and speed brakes retracted) descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithm is described. The results of the flight tests flown with the Terminal Configured Vehicle airplane are presented.

A Cockpit Comfort Level of the Descent Capsule-Shaped Vehicles

Directory of Open Access Journals (Sweden)

V. E. Minenko

2017-01-01

Full Text Available The article formulates the task of selecting a design-layout pattern for a transport spacecraft, in terms of reaching a proper comfort level for the crew to have appropriate functioning. Using the example of a domestic spacecraft and an American one, it has been shown that the type of launch vehicle, the launch specifics, the operational overloads, and the overall mass restrictions have a dramatic impact on the choice of the design-layout pattern of the spacecraft. The free volume of the pressure cockpit per each member of the crew is considered as the main characteristic to show a level of the spacecraft comfort. Using the average statistical data on the layout density of different equipment, the article estimates the possible increase of this characteristic for the cutting-edge descent vehicles. Using the example of the descent vehicles of Soyuz and Apollo class, the article shows a dependence of the raising weight of a descent vehicle on the free volume of its pressure cockpit. Attention is drawn to the fact that the limit of increasing free space of the spacecraft compartments to achieve maximum comfort should correspond to a set of functions that the crew performs in the compartments considered. Otherwise, the increase in the spacecraft mass will prove to be unjustified. The results stated in the article can be useful to developers of manned spacecraft, as well as to teachers and students. In the long term it is worthwhile adding the article material with the mass and volume indicators, as well as with the estimate results of the comfort level of modern manned spacecrafts being under design in Russia and USA, such as PTK NP (“Federation”, “Orion”, “Dragon V2”.

Studies of the Ecophysiology of Single Cells in Microbial Communities by (Quantitative) Microautoradiography and Fluorescence In Situ Hybridization (MAR-FISH)

DEFF Research Database (Denmark)

Nierychlo, Marta; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

2015-01-01

image analysis (MARQuant). Quantification of MAR signals can answer more specific questions regarding metabolic activity and function of the microbes. Here, we give an overview of how to use MAR-FISH in various ecosystems and provide a detailed protocol for MAR-FISH, including sampling, incubation...

Block-Based Gradient Descent for Local Backlight Dimming and Flicker Reduction

DEFF Research Database (Denmark)

Burini, Nino; Mantel, Claire; Nadernejad, Ehsan

2014-01-01

Local backlight dimming technology is a two-fold improvement for LED backlit LCD screens that allows to reduce power consumption and increase visual quality. This paper presents a fast version of an iterative backlight dimming algorithm based on gradient descent search. The speed is increased...

Mechanical Aqueous Alteration Dominates Textures of Gale Crater Rocks: Mars Hand Lens Imager (MAHLI) Results

Science.gov (United States)

Aileen Yingst, R.; Minitti, Michelle; Edgett, Kenneth; McBride, Marie; Stack, Kathryn

2015-04-01

The Mars Hand Lens Imager (MAHLI) acquired sub-mm/pixel scale color images of over 70 individual rocks and outcrops during Curiosity's first year on Mars, permitting the study of textures down to the distinction between silt and very fine sand. We group imaged rock textures into classes based on their grain size, sorting, matrix characteristics, and abundance of pores. Because the recent campaign at Pahrump Hills acquired many more MAHLI images than elsewhere along the rover traverse [6], textural analysis there is more detailed and thus types observed there are sub-divided. Mudstones: These rocks contain framework grains smaller than the highest resolution MAHLI images (16 μm/pixel), and thus are interpreted to consist of grains that are silt-sized or smaller. Some rocks contain nodules, sulfate veins, and Mg-enriched erosionally-resistant ridges. The Pahrump Hills region contains mudstones of at least four different sub-textures: recessive massive, recessive parallel-laminated, resistant laminated-to-massive, and resistant cross-stratified. Recessive mudstones are slope-forming; parallel-laminated recessive mudstones display mm-scale parallel (and in some cases rhythmic) lamination that extends laterally for many meters, and are interbedded with recessive massive mudstones. Coarse cm- to mm-scale laminae appear within resistant mudstones though some portions are more massive; laminae tend to be traceable for cm to meters. Well-sorted sandstones: Rocks in this class are made of gray, fine-to-medium sand and exhibit little to no porosity. Two examples of this class show fine lineations with sub-mm spacing. Aillik, a target in the Shaler outcrop, shows abundant cross-lamination. The Pahrump Hills region contains a sub-texture of well-sorted, very fine to fine-grained cross-stratified sandstone at the dune and ripple-scale. Poorly-sorted sandstones. This class is subdivided into two sub-classes: rounded, coarse-to-very coarse sand grains of variable colors and

Manifold regularized discriminative nonnegative matrix factorization with fast gradient descent.

Science.gov (United States)

Guan, Naiyang; Tao, Dacheng; Luo, Zhigang; Yuan, Bo

2011-07-01

Nonnegative matrix factorization (NMF) has become a popular data-representation method and has been widely used in image processing and pattern-recognition problems. This is because the learned bases can be interpreted as a natural parts-based representation of data and this interpretation is consistent with the psychological intuition of combining parts to form a whole. For practical classification tasks, however, NMF ignores both the local geometry of data and the discriminative information of different classes. In addition, existing research results show that the learned basis is unnecessarily parts-based because there is neither explicit nor implicit constraint to ensure the representation parts-based. In this paper, we introduce the manifold regularization and the margin maximization to NMF and obtain the manifold regularized discriminative NMF (MD-NMF) to overcome the aforementioned problems. The multiplicative update rule (MUR) can be applied to optimizing MD-NMF, but it converges slowly. In this paper, we propose a fast gradient descent (FGD) to optimize MD-NMF. FGD contains a Newton method that searches the optimal step length, and thus, FGD converges much faster than MUR. In addition, FGD includes MUR as a special case and can be applied to optimizing NMF and its variants. For a problem with 165 samples in R(1600), FGD converges in 28 s, while MUR requires 282 s. We also apply FGD in a variant of MD-NMF and experimental results confirm its efficiency. Experimental results on several face image datasets suggest the effectiveness of MD-NMF.

Using Mars Mission Analogs and Authentic Experiences to Stimulate STEM Learning in K-14 Students

Science.gov (United States)

Klug, S. L.; Grigsby, B.; Valderrama, P.; Watt, K.

2005-12-01

Today, in many of the classrooms across our nation, K-12 educators are finding it more difficult to engage their students in the subjects that will help them to succeed to a more productive way of life - science, technology, engineering, and math (STEM). Finally, add to this formidable task a diverse set of learners (demographically and skill level) of an average classroom and the constraints of high stakes testing. Quite a challenge, indeed! The Arizona State University (ASU) Mars Education Program, in partnership with the Jet Propulsion Laboratory Mars Public Engagement Team have created programming, curriculum, and activities that help to bridge the gap between STEM learning and student interest. Starting with the Standards in the STEM areas - the areas which teachers are tasked to teach already, our team has modeled the STEM-based curriculum after the way that NASA's Mars team conducts their work and research. There is much challenge in the statement "Science for All Americans" when it comes to applying it equally to all classrooms across the U.S. To make sure that these curricular materials and hands-on experiences are available to any teacher and student, the ASU Mars Education Program has adopted a "high-tech, low-tech, and no-tech" approach. In other words, materials and programming have to be available and doable with whatever capabilities a classroom might possess. Using this approach, successful examples of Mars-based educational materials include Marsbound and the Mars Student Imaging Project. The Marsbound simulation is based on National Technology Standards and seemingly low tech. However, the simplicity of this simulation is quickly forgotten as it follows the familiar NASA scenario of building a mission to Mars with engineering constraints. Student teams use a set of equipment cards and a playmat (both available at no cost) to build their mission and balance it according to the constraints given. Students soon realize there is a lot of complexity to

Mars Thermal Inertia

Science.gov (United States)

2001-01-01

This image shows the global thermal inertia of the Martian surface as measured by the Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor. The data were acquired during the first 5000 orbits of the MGS mapping mission. The pattern of inertia variations observed by TES agrees well with the thermal inertia maps made by the Viking Infrared Thermal Mapper experiment, but the TES data shown here are at significantly higher spatial resolution (15 km versus 60 km).The TES instrument was built by Santa Barbara Remote Sensing and is operated by Philip R. Christensen, of Arizona State University, Tempe, AZ.

SHERLOC: An investigation for Mars 2020

Science.gov (United States)

Beegle, Luther; Bhartia, Rohit

2016-04-01

SHERLOC is a Deep UV (DUV) native fluorescence and resonance Raman spectrometer that was selected as part of the Mars 2020 payload. It is a robotic arm mounted instrument that utilizes a DUV laser to generate characteristic Raman and fluorescence photons from a targeted spot. The DUV laser is co-boresighted to a context imager and integrated into an autofocusing/scanning optical system that allows us to correlate spectral signatures to surface textures, morphology and visible features. Additionally, it has recently been augmented with an imaging system that is a built-to-print version of the MArs Hand Lens Imager (MAHLI) instrument on the Mars Science Laboratory (MSL). Through the use of an internal scanning mirror, autofocusing lens, and a depth of focus of ±500 μm, the 100 μm laser spot can be systematically scanned over a 7x7 mm area with a fine-scale spatial resolution on natural or abraded surfaces and boreholes to a depth of at least 13 mm, without further arm movement. Through the use of the context imager, SHERLOC's data products can be combined with observations made by other instruments on the Mars 2020 payload. By bringing to bear multiple scientific instruments on a single sample, our ability to assess the habitability of ancient environments and search for potential biosignatures preserved within the geologic record will be greatly enhanced, making possible the selection of high-priority samples for caching. The SHERLOC investigation combines two spectral phenomena, fluorescence and pre-resonance/resonance DUV Raman scattering. These spectral features are resolvable when a high-radiance, narrow line-width, laser source illuminates a sample. In fluorescence, the incident photons are absorbed and re-emitted at a longer wavelength. The difference between the excitation and emission wavelength is the difference between the excitation frequency and the lowest electronic state frequency that increases with increasing aromatic structure (i.e., number of

Cars on Mars

Science.gov (United States)

Landis, Geoffrey A.

2002-01-01

Mars is one of the most fascinating planets in the solar system, featuring an atmosphere, water, and enormous volcanoes and canyons. The Mars Pathfinder, Global Surveyor, and Odyssey missions mark the first wave of the Planet Earth's coming invasion of the red planet, changing our views of the past and future of the planet and the possibilities of life. Scientist and science-fiction writer Geoffrey A. Landis will present experiences on the Pathfinder mission, the challenges of using solar power on the surface of Mars, and present future missions to Mars such as the upcoming Mars Twin Rovers, which will launch two highly-capable vehicles in 2003 to explore the surface of Mars.

Observations of CO on Mars with OMEGA/Mars Express: A Study of Local Variations over the Volcanoes

Science.gov (United States)

Encrenaz, T.; Drossart, P.; Fouchet, T.; Melchiorri, R.; Lellouch, E.; Combes, M.; Bibring, J.-P.; Moroz, V.; Ignatiev, N.; Forget, F.; OMEGA Team

Spectra of Mars recorded with the OMEGA/Mars Express experiment have been used to retrieve information on the CO mixing ratio over the planet. By using simultaneously the CO (1-0) band at 4.7 microns and a weak CO2 band at 4.85 microns, we have inferred the CO mixing ratio in all regions where the thermal emission is dominent, i.e. where the surface temperature is maximum. These observations, in particular, indicate a significant depletion of the CO/CO2 ratio over Olympus Mons. This preliminary result seems to confirm the analysis performed by the ISM imaging spectrometer aboard the Phobos mission, which suggested a possible depletion of CO over the volcanoes (Rosenqvist et al., Icarus 98, 254, 1992). Implications of this result will be discussed.

An independent assessment of the technical feasibility of the Mars One mission plan - Updated analysis

Science.gov (United States)

Do, Sydney; Owens, Andrew; Ho, Koki; Schreiner, Samuel; de Weck, Olivier

2016-03-01

In recent years, the Mars One program has gained significant publicity for its plans to colonize the red planet. Beginning in 2025, the program plans to land four people on Mars every 26 months via a series of one-way missions, using exclusively existing technology. This one-way approach has frequently been cited as a key enabler of accelerating the first crewed landing on Mars. While the Mars One program has received considerable attention, little has been published in the technical literature regarding the formulation of its mission architecture. In light of this, we perform an independent analysis of the technical feasibility of the Mars One mission plan, focusing on the architecture of the life support and in-situ resource utilization (ISRU) systems, and their impact on sparing and space logistics. To perform this analysis, we adopt an iterative analysis approach in which we model and simulate the mission architecture, assess its feasibility, implement any applicable modifications while attempting to remain within the constraints set forth by Mars One, and then resimulate and reanalyze the revised version of the mission architecture. Where required information regarding the Mars One mission architecture is not available, we assume numerical values derived from standard spaceflight design handbooks and documents. Through four iterations of this process, our analysis finds that the Mars One mission plan, as publicly described, is not feasible. This conclusion is obtained from analyses based on mission assumptions derived from and constrained by statements made by Mars One, and is the result of the following findings: (1) several technologies including ISRU, life support, and entry, descent, and landing (EDL) are not currently "existing, validated and available" as claimed by Mars One; (2) the crop growth area described by Mars One is insufficient to feed their crew; (3) increasing the crop growth area to provide sufficient food for the crew leads to atmospheric

The q-G method : A q-version of the Steepest Descent method for global optimization.

Science.gov (United States)

Soterroni, Aline C; Galski, Roberto L; Scarabello, Marluce C; Ramos, Fernando M

2015-01-01

In this work, the q-Gradient (q-G) method, a q-version of the Steepest Descent method, is presented. The main idea behind the q-G method is the use of the negative of the q-gradient vector of the objective function as the search direction. The q-gradient vector, or simply the q-gradient, is a generalization of the classical gradient vector based on the concept of Jackson's derivative from the q-calculus. Its use provides the algorithm an effective mechanism for escaping from local minima. The q-G method reduces to the Steepest Descent method when the parameter q tends to 1. The algorithm has three free parameters and it is implemented so that the search process gradually shifts from global exploration in the beginning to local exploitation in the end. We evaluated the q-G method on 34 test functions, and compared its performance with 34 optimization algorithms, including derivative-free algorithms and the Steepest Descent method. Our results show that the q-G method is competitive and has a great potential for solving multimodal optimization problems.

The magnetic field of Mars according to data of Mars-3 and Mars-5 space vehicles

International Nuclear Information System (INIS)

Dolginov, Sh.Sh.; Eroshenko, E.G.; Zhuzgov, L.N.

1975-01-01

Magnitograms obtained by the space probe ''Mars-5'' on the evening and day sides as well as those from the ''Mars-3'' obtained earlier suggest the following: In the vicinity of Mars there exists a shock front and its disposition is tracked at various angles to the direction to the sun. Magnetometers have registered a region in space where magnetic field features the properties of a magnetosphere field in its topology and action on plasma. The magnetic field in the region of the ''magnitosphere'' does not change its sign when the interplanetary field does shile in adjacent boundary regions the regular part of the field changes its sign when that of the interplanetary field does. The configuration and dimensions of the ''magnitosphere'' depend on thesolar wind intensity. On the day side (''Mars-3'') the magnitospheric field ceases to be registered at an altitude of 2200km, whereas on the night side (''Mars-5'') the regular field is traced up to 7500-9500km from the planet surface. All the above unambiguously suggests that the planet Mars has its own magnetic field. Under the influence of the solar wind the field takes the characteristic form: it is limited on the day side and elongated on the night one. The topology oif force lines is explicable if one assumes that the axis of the Mars magnetic dipole is inclined to the rotation axis at an abgle of 15-20deg. The northern magnetic pole of the dipole is licated in the northern hemisphere, i.e. the Mars fields in their regularity are opposite to the geomagnetic field. The magnetic moment of the Mars dipole is equal to M=2.5x10 22 Gauss.cm 3 . (author)

Muon radiography for exploration of Mars geology

Directory of Open Access Journals (Sweden)

S. Kedar

2013-06-01

Full Text Available Muon radiography is a technique that uses naturally occurring showers of muons (penetrating particles generated by cosmic rays to image the interior of large-scale geological structures in much the same way as standard X-ray radiography is used to image the interior of smaller objects. Recent developments and application of the technique to terrestrial volcanoes have demonstrated that a low-power, passive muon detector can peer deep into geological structures up to several kilometers in size, and provide crisp density profile images of their interior at ten meter scale resolution. Preliminary estimates of muon production on Mars indicate that the near horizontal Martian muon flux, which could be used for muon radiography, is as strong or stronger than that on Earth, making the technique suitable for exploration of numerous high priority geological targets on Mars. The high spatial resolution of muon radiography also makes the technique particularly suited for the discovery and delineation of Martian caverns, the most likely planetary environment for biological activity. As a passive imaging technique, muon radiography uses the perpetually present background cosmic ray radiation as the energy source for probing the interior of structures from the surface of the planet. The passive nature of the measurements provides an opportunity for a low power and low data rate instrument for planetary exploration that could operate as a scientifically valuable primary or secondary instrument in a variety of settings, with minimal impact on the mission's other instruments and operation.

Evidence for Basinwide Mud Volcanism in Acidalia Planitia, Mars

Science.gov (United States)

Oehler, Dorothy Z.; Allen, Carlton C.

2010-01-01

High-albedo mounds in Acidalia Planitia occur in enormous numbers. They have been variously interpreted as pseudocraters, cinder cones, tuff cones, pingos, ice disintegration features, or mud volcanoes. Our work uses regional mapping, basin analysis, and new data from the Context Camera (CTX), High Resolution Imaging Science Experiment (HiRISE), and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) to re-assess the origin and significance of these structures.

Mars

CERN Document Server

Payment, Simone

2017-01-01

This curriculum-based, fun, and approachable book offers everything young readers need to know to begin their study of the Red Planet. They will learn about the fundamental aspects of the Mars, including its size, mass, surface features, interior, orbit, and spin. Further, they will learn about the history of the missions to Mars, including the Viking spacecraft and the Curiosity and MAVEN rovers. Finally, readers will learn about why scientists think there's a chance that Mars is or was suitable for life. With stunning imagery from NASA itself, readers will have a front seat-view of the missi

Not of African Descent: Dental Modification among Indigenous Caribbean People from Canímar Abajo, Cuba.

Science.gov (United States)

Roksandic, Mirjana; Alarie, Kaitlynn; Rodríguez Suárez, Roberto; Huebner, Erwin; Roksandic, Ivan

2016-01-01

Dental modifications in the Caribbean are considered to be an African practice introduced to the Caribbean archipelago by the influx of enslaved Africans during colonial times. Skeletal remains which exhibited dental modifications are by default considered to be Africans, African descendants, or post-contact indigenous people influenced by an African practice. Individual E-105 from the site of Canímar Abajo (Cuba), with a direct 14C AMS date of 990-800 cal BC, provides the first unequivocal evidence of dental modifications in the Antilles prior to contact with Europeans in AD 1492. Central incisors showing evidence of significant crown reduction (loss of crown volume regardless of its etiology) were examined macroscopically and with a scanning electron microscope (SEM) to determine if the observed alterations were due to deliberate modification or other (unintentional) factors considered: postmortem breakage, violent accidental breakage, non-dietary use of teeth, and wear caused by habitual or repeated actions. The pattern of crown reduction is consistent with deliberate dental modification of the type commonly encountered among African and African descendent communities in post-contact Caribbean archaeological assemblages. Six additional individuals show similar pattern of crown reduction of maxillary incisors with no analogous wear in corresponding mandibular dentition.

A rare case of mixed gonadal dysgenesis: 45, X0/ 46, X, +mar 1/ 46, X, +mar 2

Directory of Open Access Journals (Sweden)

Carolina Talini

2016-07-01

Full Text Available This study aims to report a rare case of mixed gonadal dysgenesis with mosaicism pattern 45 X0 / 46, X, +mar 1/ 46, X, +mar 2. Patient referred to the pediatric urology service with 2 months of age. Right after the baby was born it was not possible do determine the baby's gender. The karyotype was inconclusive: 45, X0. Contrast genitography and uretrocystogram showed a single perineal orifice below the micropenis and between the bifid scrotum, opacification of the bladder with male aspect urethra during urination and short penile urethra. There was also opacification of the posterior vaginal cavity with low junction to the posterior urethra and a linear opacity image suggesting uterine canal. Laparoscopy revealed bilateral gonadal bands and spermatic elements entering the inguinal canal. Müllerian derivatives were absent. Gonadal biopsy was performed and concluded that these were abnormal infantile testes. Microarray testing took a few months and resulted in: 45 X0 / 46, X, +mar 1/ 46, X, +mar 2. Patient was kept on topic androstenedione for 6 months and then underwent penoscrotal hypospadias correction. Mosaic chromosomal pattern is a rare condition that can present with a wide variety of phenotypes. Early recognition has important implications on these patients’ social and psychological life and also for their proper management.

The Mars Hopper: Development, Simulation and Experimental Validation of a Radioisotope Exploration Probe for the Martian Surface

Energy Technology Data Exchange (ETDEWEB)

Nathan D. Jerred; Spencer Cooley; Robert C. O' Brien; Steven D. Howe; James E. O' Brien

2012-09-01

An advanced exploration probe has been proposed by the Center for Space Nuclear Research (CSNR) to acquire detailed data from the Martian surface and subsurface, ‘hop’ large distances to multiple sites in short periods of time and perform this task repeatedly. Although several similar flying vehicles have been proposed utilizing various power sources and complex designs, e.g. solar-electric and chemical-based, the CSNR’s Mars Hopper is based on a radioisotope thermal rocket (RTR) concept. The Mars Hopper’s design relies on the high specific energies [J/kg] of radioisotopes and enhances their low specific power [W/kg] through the use of a thermal capacitance material to store thermal energy over time. During operation, the RTR transfers the stored thermal energy to a flowing gas, which is then expanded through a converging-diverging nozzle, producing thrust. Between flights, the platform will have ample time to perform in-depth science at each location while the propellant tanks and thermal capacitor recharge. Recharging the propellant tanks is accomplished by sublimation freezing of the ambient CO2 atmosphere with a cryocooler, followed by heating and pressurization to yield a liquid storage state. The proposed Mars Hopper will undergo a ballistic flight, consuming the propellant in both ascent and descent, and by using multiple hopper platforms, information can be gathered on a global scale, enabling better resource resolution and providing valuable information for a possible Mars sample-return mission. The CSNR, collaborating with the Idaho National Laboratory (INL) and three universities (University of Idaho, Utah State University and Oregon State University), has identified key components and sub-systems necessary for the proposed hopper. Current project activities include the development of a lab-scale prototypic Mars Hopper and test facility, along with computational fluid dynamics (CFD)/thermal-hydraulic models to yield a better understanding of the

Are pregnant women of non-Northern European descent more anaemic than women of Northern European descent? A study into the prevalence of anaemia in pregnant women in Amsterdam.

NARCIS (Netherlands)

Jans, S.M.; Daemers, D.O.A.; Vos, R.; Lagro-Janssen, A.L.M.

2009-01-01

OBJECTIVES: to investigate the prevalence of anaemia in pregnancy according to the cut-off points used in the national clinical guideline 'Anaemia in Primary Care Midwifery Practice', and to investigate a possible difference in prevalence between pregnant women of Northern European descent compared

The humanation of Mars

Science.gov (United States)

David, L. W.

Early developments related to human excursions to Mars are examined, taking into account plans considered by von Braun, and the 'ambitious goal of a manned flight to Mars by the end of the century', proposed at the launch of Apollo 11. In response to public reaction, plans for manned flights to Mars in the immediate future were given up, and unmanned reconnaissance of Mars was continued. An investigation is conducted concerning the advantages of manned exploration of Mars in comparison to a study by unmanned space probes, and arguments regarding a justification for interplanetary flight to Mars are discussed. Attention is given to the possibility to consider Mars as a 'back-up' planet for preserving earth life, an international Mars expedition as a world peace project, the role of Mars in connection with resource utilization considerations, and questions of exploration ethics.

Mars Drilling Status

Science.gov (United States)

Mandell, Humboldt, C., Jr.

2002-01-01

This slide presentation reviews the current status of work to explore Mars beneath the surface of planet. One of the objective of this work is to enable further exploration of Mars by humans. One of the requirements for this is to find water on Mars. The presences of water is critical for Human Exploration and a permanent presence on Mars. If water is present beneath the surface it is the best chance of finding life on Mars. The presentation includes a timeline showing the robotic missions, those that have already been on Mars, and planned missions, an explanation of why do we want to drill on Mars, and some of the challenges, Also include are reviews of a missions that would drill 200 and 4,000 to 6,000 meters into the Martian bedrock, and a overview description of the drill. There is a view of some places where we have hopes of finding water.

NASA's strategy for Mars exploration in the 1990s and beyond

Science.gov (United States)

Huntress, W. T.; Feeley, T. J.; Boyce, J. M.

NASA's Office of Space Science is changing its approach to all its missions, both current and future. Budget realities are necessitating that we change the way we do business and the way we look at NASA's role in the U.S. Government. These challenges are being met by a new and innovative approach that focuses on achieving a balanced world-class space science program that requires less U.S. resources while providing an enhanced role for technology and education as integral components of our Research and Development (R&D) programs. Our Mars exploration plans, especially the Mars Surveyor program, are a key feature of this new NASA approach to space science. The Mars Surveyor program will be affordable, engaging to the public with global and close-up images of Mars, have high scientific value, employ a distributed risk strategy (two launches per opportunity), and will use significant advanced technologies.

Geologic context of recurring slope lineae in Melas and Coprates Chasmata, Mars

Science.gov (United States)

Chojnacki, Matthew; McEwen, Alfred; Dundas, Colin M.; Ojha, Lujendra; Urso, Anna; Sutton, Sarah

2016-01-01

One of the major Mars discoveries of recent years is the existence of recurring slope lineae (RSL), which suggests that liquid water occurs on or near the surface of Mars today. These dark and narrow features emerge from steep, rocky exposures and incrementally grow, fade, and reform on a seasonal basis and are detected in images from the High Resolution Imaging Science Experiment camera. RSL are known to occur at scattered midlatitude and equatorial sites with little spatial connection to one another. One major exception is the steep, low-albedo slopes of Melas and Coprates Chasmata, in Valles Marineris where RSL are detected among diverse geologic surfaces (e.g., bedrock and talus) and landforms (e.g., inselbergs and landslides). New images show topographic changes including sediment deposition on active RSL slopes. Midwall locations in Coprates and Melas appear to have more areally extensively abundant RSL and related fans as compared with other RSL sites found on Mars. Water budget estimates for regional RSL are on the order of 105 to 106 m3 of fluid, for depths of 10 to 100mm, and suggest that a significant amount of near-surface watermight be present. Many RSL are concentrated near local topographic highs, such as ridge crests or peaks, which is challenging to explain via groundwater or ice without a recharge mechanism. Collectively, results provide additional support for the notion that significant amounts of near-surface water can be found on Mars today and suggest that a widespread mechanism, possibly related to the atmosphere, is recharging RSL sources.

Medical Archive Recording System (MARS)

OpenAIRE

Mohammad Reza Tajvidi

2007-01-01

In this talk, one of the most efficient, and reliable integrated tools for CD/DVD production workflow, called Medical Archive Recording System (MARS) by ETIAM Company, France, which is a leader in multimedia connectivity for healthcare in Europe, is going to be introduced. "nThis tool is used to record all patient studies, route the studies to printers and PACS automatically, print key images and associated reports and log all study production for automated post processing/archiving. Its...

Stochastic Spectral and Conjugate Descent Methods

KAUST Repository

Kovalev, Dmitry

2018-02-11

The state-of-the-art methods for solving optimization problems in big dimensions are variants of randomized coordinate descent (RCD). In this paper we introduce a fundamentally new type of acceleration strategy for RCD based on the augmentation of the set of coordinate directions by a few spectral or conjugate directions. As we increase the number of extra directions to be sampled from, the rate of the method improves, and interpolates between the linear rate of RCD and a linear rate independent of the condition number. We develop and analyze also inexact variants of these methods where the spectral and conjugate directions are allowed to be approximate only. We motivate the above development by proving several negative results which highlight the limitations of RCD with importance sampling.

Stochastic Spectral and Conjugate Descent Methods

KAUST Repository

Kovalev, Dmitry; Gorbunov, Eduard; Gasanov, Elnur; Richtarik, Peter

2018-01-01

The state-of-the-art methods for solving optimization problems in big dimensions are variants of randomized coordinate descent (RCD). In this paper we introduce a fundamentally new type of acceleration strategy for RCD based on the augmentation of the set of coordinate directions by a few spectral or conjugate directions. As we increase the number of extra directions to be sampled from, the rate of the method improves, and interpolates between the linear rate of RCD and a linear rate independent of the condition number. We develop and analyze also inexact variants of these methods where the spectral and conjugate directions are allowed to be approximate only. We motivate the above development by proving several negative results which highlight the limitations of RCD with importance sampling.

The Regulatory Small RNA MarS Supports Virulence of Streptococcus pyogenes.

Science.gov (United States)

Pappesch, Roberto; Warnke, Philipp; Mikkat, Stefan; Normann, Jana; Wisniewska-Kucper, Aleksandra; Huschka, Franziska; Wittmann, Maja; Khani, Afsaneh; Schwengers, Oliver; Oehmcke-Hecht, Sonja; Hain, Torsten; Kreikemeyer, Bernd; Patenge, Nadja

2017-09-25

Small regulatory RNAs (sRNAs) play a role in the control of bacterial virulence gene expression. In this study, we investigated an sRNA that was identified in Streptococcus pyogenes (group A Streptococcus, GAS) but is conserved throughout various streptococci. In a deletion strain, expression of mga, the gene encoding the multiple virulence gene regulator, was reduced. Accordingly, transcript and proteome analyses revealed decreased expression of several Mga-activated genes. Therefore, and because the sRNA was shown to interact with the 5' UTR of the mga transcript in a gel-shift assay, we designated it MarS for m ga-activating regulatory sRNA. Down-regulation of important virulence factors, including the antiphagocytic M-protein, led to increased susceptibility of the deletion strain to phagocytosis and reduced adherence to human keratinocytes. In a mouse infection model, the marS deletion mutant showed reduced dissemination to the liver, kidney, and spleen. Additionally, deletion of marS led to increased tolerance towards oxidative stress. Our in vitro and in vivo results indicate a modulating effect of MarS on virulence gene expression and on the pathogenic potential of GAS.

Are pregnant women of non-Northern European descent more anaemic than women of Northern European descent? A study into the prevalence of anaemia in pregnant women in Amsterdam

NARCIS (Netherlands)

Jans, S. M. P. J.; Daemers, D. O. A.; de Vos, R.; Lagro-Jansen, A. L. M.

2009-01-01

to investigate the prevalence of anaemia in pregnancy according to the cut-off points used in the national clinical guideline 'Anaemia in Primary Care Midwifery Practice', and to investigate a possible difference in prevalence between pregnant women of Northern European descent compared with women

Are pregnant women of non-Northern European descent more anaemic than women of Northern European descent? A study into the prevalence of anaemia in pregnant women in Amsterdam

NARCIS (Netherlands)

Jans, S.M.P.J.; Daemers, D.O.A.; Vos, R. de; Lagro-Janssen, A.L.M.

2009-01-01

Objectives - to investigate the prevalence of anaemia in pregnancy according to the cut-off points used in the national clinical guideline ‘Anaemia in Primary Care Midwifery Practice’, and to investigate a possible difference in prevalence between pregnant women of Northern European descent compared

Farewell to the Earth and the Moon -ESA's Mars Express successfully tests its instruments

Science.gov (United States)

2003-07-01

The routine check-outs of Mars Express's instruments and of the Beagle-2 lander, performed during the last weeks, have been very successful. "As in all space missions little problems have arisen, but they have been carefully evaluated and solved. Mars Express continues on its way to Mars performing beautifully", comments Chicarro. The views of the Earth/Moon system were taken on 3 July 2003 by Mars Express's High Resolution Stereo Camera (HRSC), when the spacecraft was 8 million kilometres from Earth. The image taken shows true colours; the Pacific Ocean appears in blue, and the clouds near the Equator and in mid to northern latitudes in white to light grey. The image was processed by the Instrument Team at the Institute of Planetary Research of DLR, Berlin (Germany). It was built by combining a super resolution black and white HRSC snap-shot image of the Earth and the Moon with colour information obtained by the blue, green, and red sensors of the instrument. “The pictures and the information provided by the data prove the camera is working very well. They provide a good indication of what to expect once the spacecraft is in its orbit around Mars, at altitudes of only 250-300 kilometres: very high resolution images with brilliant true colour and in 3D,” says the Principal Investigator of the HRSC, Gerhard Neukum, of the Freie Universität of Berlin (Germany). This camera will be able to distinguish details of up to 2 metres on the Martian surface. Another striking demonstration of Mars Express's instruments high performance are the data taken by the OMEGA spectrometer. Once at Mars, this instrument will provide the best map of the molecular and mineralogical composition of the whole planet, with 5% of the planetary surface in high resolution. Minerals and other compounds such as water will be charted as never before. As the Red Planet is still too far away, the OMEGA team devised an ingenious test for their instrument: to detect the Earth’s surface

Micro-mapping Meteorite Surfaces on Mars using Microscopic Imager Mosaics — A Tool for Unraveling Weathering History at Meridiani Planum

Science.gov (United States)

Ashley, J. W.; Herkenhoff, K. E.; Golombek, M. P.; Johnson, J. R.

2012-12-01

Meteorites found on Mars provide valuable insights into martian surface processes. During the course of Mars Exploration Rover (MER) extended missions, Spirit and Opportunity have identified 17 confirmed and candidate meteorites on Mars, most of which are irons. The iron meteorites exhibit morphologies and coatings that communicate complex post-fall exposure histories relevant to an understanding of climate near the martian equator [1-4]. Both chemical and mechanical weathering effects are represented. Among the more significant of these are: 1) cm-scale hollowing, 2) surficial rounding, 3) mass excavation/dissolution and removal, 4) differential etching of kamacite plates and taenite lamellae, revealing Widmanstätten patterns, 5) discontinuous iron oxide coatings, and 6) the effects of cavernous weathering, which often penetrate to rock interiors. Determining the nature, magnitude, and timing of each process and its associated features is a complex problem that will be aided by laboratory experiments, image processing, and careful surface evaluation. Because some features appear to superpose others in ways analogous to stratigraphic relationships, Microscopic Imager (MI) mosaics are useful for sketching "geologic maps" of meteorite surfaces. Employing the techniques of conventional planetary mapping [5], each map was drafted manually using full-resolution MI mosaics and Adobe Photoshop software. Units were selected to represent the oxide coating, dust-coated surfaces, sand-coated surfaces, taenite lamellae, and uncoated metal. Also included are areas in shadow, and regions of blooming caused by specular reflection of metal. Regmaglypt rim crests are presented as lineations. As with stratigraphic relationships, noting embayments and other cross-cutting relationships assists with establishing the relative timing for observed weathering effects. In addition to suggesting alternating sequences of wind and water exposure [1], patterns in oxide coating occurrence show

Exploring Mars

Science.gov (United States)

Breuil, Stéphanie

2016-04-01

Mars is our neighbour planet and has always fascinated humans as it has been seen as a potential abode for life. Knowledge about Mars is huge and was constructed step by step through numerous missions. It could be difficult to describe these missions, the associated technology, the results, the questions they raise, that's why an activity is proposed, that directly interests students. Their production is presented in the poster. Step 1: The main Mars feature and the first Mars explorations using telescope are presented to students. It should be really interesting to present "Mars Canals" from Percival Lowell as it should also warn students against flawed interpretation. Moreover, this study has raised the big question about extra-terrestrial life on Mars for the first time. Using Google Mars is then a good way to show the huge knowledge we have on the planet and to introduce modern missions. Step 2: Students have to choose and describe one of the Mars mission from ESA and NASA. They should work in pairs. Web sites from ESA and NASA are available and the teacher makes sure the main missions will be studied. Step 3: Students have to collect different pieces of information about the mission - When? Which technology? What were the main results? What type of questions does it raise? They prepare an oral presentation in the form they want (role play, academic presentation, using a poster, PowerPoint). They also have to produce playing cards about the mission that could be put on a timeline. Step 4: As a conclusion, the different cards concerning different missions are mixed. Groups of students receive cards and they have to put them on a timeline as fast as possible. It is also possible to play the game "timeline".

Mars

CERN Document Server

Day, Trevor

2006-01-01

Discusses the fundamental facts concerning this mysterious planet, including its mass, size, and atmosphere, as well as the various missions that helped planetary scientists document the geological history of Mars. This volume also describes Mars'' seasons with their surface effects on the planet and how they have changed over time.

Anticipatory kinematics and muscle activity preceding transitions from level-ground walking to stair ascent and descent.

Science.gov (United States)

Peng, Joshua; Fey, Nicholas P; Kuiken, Todd A; Hargrove, Levi J

2016-02-29

The majority of fall-related accidents are during stair ambulation-occurring commonly at the top and bottom stairs of each flight, locations in which individuals are transitioning to stairs. Little is known about how individuals adjust their biomechanics in anticipation of walking-stair transitions. We identified the anticipatory stride mechanics of nine able-bodied individuals as they approached transitions from level ground walking to stair ascent and descent. Unlike prior investigations of stair ambulation, we analyzed two consecutive "anticipation" strides preceding the transitions strides to stairs, and tested a comprehensive set of kinematic and electromyographic (EMG) data from both the leading and trailing legs. Subjects completed ten trials of baseline overground walking and ten trials of walking to stair ascent and descent. Deviations relative to baseline were assessed. Significant changes in mechanics and EMG occurred in the earliest anticipation strides analyzed for both ascent and descent transitions. For stair descent, these changes were consistent with observed reductions in walking speed, which occurred in all anticipation strides tested. For stair ascent, subjects maintained their speed until the swing phase of the latest anticipation stride, and changes were found that would normally be observed for decreasing speed. Given the timing and nature of the observed changes, this study has implications for enhancing intent recognition systems and evaluating fall-prone or disabled individuals, by testing their abilities to sense upcoming transitions and decelerate during locomotion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nurses of African descent and career advancement.

Science.gov (United States)

Wesley, Yvonne; Dobal, May T

2009-01-01

The purpose of this article is to evaluate a leadership institute designed to promote career advancement and leadership in administration, education, and research among nurses of African descent. Government reports indicate that Black Americans receive lower quality health care than other racial groups even when insurance and income are equal. Moreover, the literature suggests that less than 10% of practicing professional nurses in America are Black-and of these, less than 1% are in senior executive leadership positions. However, the literature lacks detailed discussion of the effectiveness of leadership programs. This article provides an in-depth look at a leadership institute for Black nurses and outlines the impact of the program.

Processing of A New Digital Orthoimage Map of The Martian Western Hemisphere Using Data Obtained From The Mars Orbiter Camera At A Resolution of 256 Pixel/deg

Science.gov (United States)

Wählisch, M.; Niedermaier, G.; van Gasselt, S.; Scholten, F.; Wewel, F.; Roatsch, T.; Matz, K.-D.; Jaumann, R.

We present a new digital orthoimage map of Mars using data obtained from the CCD line scanner Mars Orbiter Camera (MOC) of the Mars Global Surveyor Mis- sion (MGS) [1,2]. The map covers the Mars surface from 0 to 180 West and from 60 South to 60 North with the MDIM2 resolution of 256 pixel/degree and size. Image data processing has been performed using multiple programs, developed by DLR, Technical University of Berlin [3], JPL, and the USGS. 4,339 Context and 183 Geodesy images [2] were included. After radiometric corrections, the images were Mars referenced [4], geometrically corrected [5] and orthoprojected using a global Martian Digital Terrain Model (DTM) with a resolution of 64 pixel/degree, developed at DLR and based on MGS Mars Orbiter Laser Altimeter (MOLA) data [6]. To elim- inate major differences in brightness between the individual images of the mosaics, high- and low-pass filter processing techniques were applied for each image. After filtering, the images were mosaicked without registering or using block adjustment techniques in order to improve the geometric quality. It turns out that the accuracy of the navigation data has such a good quality that the orthoimages fit very well to each other. When merging the MOC mosaic with the MOLA data using IHS- trans- formation, we recognized very good correspondence between these two datasets. We create a topographic image map of the Coprates region (MC­18) adding contour lines derived from the global DTM to the mosaic. These maps are used for geological and morphological interpretations in order to review and improve our current Viking-based knowledge about the Martian surface. References: [1] www.mssss.com, [2] Caplinger, M. and M. Malin, "The Mars Or- biter Camera Geodesy Campaign, JGR, in press, [3] Scholten, F., Vol XXXI, Part B2, Wien 1996, p.351-356, [4] naïf.jpl.nasa.gov, [5] R.L.Kirk. et al. (2001), "Geometric Calibration of the Mars Orbiter Cameras and Coalignment with Mars Orbiter Laser Altimeter

Mars atmospheric water vapor abundance: 1996-1997

Science.gov (United States)

Sprague, A. L.; Hunten, D. M.; Doose, L. R.; Hill, R. E.

2003-05-01

Measurements of martian atmospheric water vapor made throughout Ls = 18.0°-146.4° (October 3, 1996-July 12, 1997) show changes in Mars humidity on hourly, daily, and seasonal time scales. Because our observing program during the 1996-1997 Mars apparition did not include concomitant measurement of nearby CO 2 bands, high northern latitude data were corrected for dust and aerosol extinction assuming an optical depth of 0.8, consistent with ground-based and HST imaging of northern dust storms. All other measurements with airmass greater than 3.5 were corrected using a total optical depth of 0.5. Three dominant results from this data set are as follows: (1) pre- and post-opposition measurements made with the slit crossing many hours of local time on Mars' Earth-facing disk show a distinct diurnal pattern with highest abundances around and slightly after noon with low abundances in the late afternoon, (2) measurements of water vapor over the Mars Pathfinder landing site (Carl Sagan Memorial Station) on July 12, 1997, found 21 ppt μm in the spatial sector centered near 19° latitude, 36° longitude while abundances around the site varied from as low as 6 to as high as 28 ppt μm, and (3) water vapor abundance is patchy on hourly and daily time scales but follows the usual seasonal trends.

Geology of Mars

International Nuclear Information System (INIS)

Soderblom, L.A.

1988-01-01

The geology of Mars and the results of the Mariner 4, 6/7, and 9 missions and the Viking mission are reviewed. The Mars chronology and geologic modification are examined, including chronological models for the inactive planet, the active planet, and crater flux. The importance of surface materials is discussed and a multispectral map of Mars is presented. Suggestions are given for further studies of the geology of Mars using the Viking data. 5 references

Laser Induced Fluorescence Imaging: Searching for Organics from the Dry Valleys of Queen Maud Land Antarctica to the Regolith and Ices of Mars

Science.gov (United States)

Storrie-Lombardi, M. C.; Sattler, B.; Muller, J.-P.; Fisk, M.; Cousins, C.; Dartnell, L.

2009-04-01

Laser induced fluorescence imaging using excitation in ultraviolet (UV) wavelengths has been proposed as a nondestructive astrobiological rapid survey tool to search for amino and nucleic acids [1], microbial life [2], and polycyclic aromatic hydrocarbons (PAHs) deep in the Mars regolith [3, 4]. However, the technique is easily adapted to search for complex biomolecular targets using longer wavelength sources [5]. Of particular interest is the ability of excitation at 532 nm to detect photosynthetic pigments in cyanobacteria-dominated microbial communities populating the ice of alpine, Arctic, and Antarctic lakes, glaciers, and ice sheets [6-8]. During the months of November and December 2008 we tested the technique as part of an extended international, interdisciplinary field campaign in the Dry Valleys of Schirmacher Oasis and Lake Untersee, Queen Maud Land, Antarctica. In this paper we review our recent laboratory experiments on the use of UV excitation for detection of PAHs doped on Mars analogue soils [9] and chasmo- and epilithic lichen communities within basaltic Iceland lavas. We present for the first time the results of our field experiments conducted during the Tawani 2008 International Antarctic Expedition for in situ detection and quantification of photosynthetic biomass in the ice caps of annual and perennially ice-covered Antarctic lakes. We discuss the advantages of using a nondestructive rapid survey photonic tools such as laser induced fluorescence imaging that can be easily implemented from lander, rover, airborne, or orbital platforms. The techniques presented can be utilized to monitor the microbial potential of large, critical ecosystems on Earth, or to facilitate the remote or manned search for organics and photosynthetic life on any terrestrial planet. References 1. Storrie-Lombardi, M.C., Hug, W.F., McDonald, G.D., Tsapin, A.I., and Nealson, K.H. 2001. Hollow cathode ion lasers for deep ultraviolet Raman spectroscopy and fluorescence imaging

The Importance of Geodetically Controlled Data Sets: THEMIS Controlled Mosaics of Mars, a Case Study

Science.gov (United States)

Fergason, R. L.; Weller, L.

2018-04-01

Accurate image registration is necessary to answer questions that are key to addressing fundamental questions about our universe. To provide such a foundational product for Mars, we have geodetically controlled and mosaicked THEMIS IR images.

The central uplift of Ritchey crater, Mars

Science.gov (United States)

Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.

2015-01-01

Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

The central uplift of Ritchey crater, Mars

Science.gov (United States)

Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.

2015-05-01

Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

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.

Is Mars Sample Return Required Prior to Sending Humans to Mars?

Science.gov (United States)

Carr, Michael; Abell, Paul; Allwood, Abigail; Baker, John; Barnes, Jeff; Bass, Deborah; Beaty, David; Boston, Penny; Brinkerhoff, Will; Budney, Charles;

Habitability & Astrobiology Research in Mars Terrestrial Analogues

Science.gov (United States)

Foing, Bernard

2014-05-01

We performed a series of field research campaigns (ILEWG EuroMoonMars) in the extreme Utah desert relevant to Mars environments, and in order to help in the interpretation of Mars missions measurements from orbit (MEX, MRO) or from the surface (MER, MSL), or Moon geochemistry (SMART-1, LRO). We shall give an update on the sample analysis in the context of habitability and astrobiology. Methods & Results: In the frame of ILEWG EuroMoonMars campaigns (2009 to 2013) we deployed at Mars Desert Research station, near Hanksville Utah, a suite of instruments and techniques [A, 1, 2, 9-11] including sample collection, context imaging from remote to local and microscale, drilling, spectrometers and life sensors. We analyzed how geological and geochemical evolution affected local parameters (mineralogy, organics content, environment variations) and the habitability and signature of organics and biota. Among the important findings are the diversity in the composition of soil samples even when collected in close proximity, the low abundances of detectable PAHs and amino acids and the presence of biota of all three domains of life with significant heterogeneity. An extraordinary variety of putative extremophiles was observed [3,4,9]. A dominant factor seems to be soil porosity and lower clay-sized particle content [6-8]. A protocol was developed for sterile sampling, contamination issues, and the diagnostics of biodiversity via PCR and DGGE analysis in soils and rocks samples [10, 11]. We compare the 2009 campaign results [1-9] to new measurements from 2010-2013 campaigns [10-12] relevant to: comparison between remote sensing and in-situ measurements; the study of minerals; the detection of organics and signs of life. Keywords: field analogue research, astrobiology, habitability, life detection, Earth-Moon-Mars, organics References [A] Foing, Stoker & Ehrenfreund (Editors, 2011) "Astrobiology field Research in Moon/Mars Analogue Environments", Special Issue of International

Evaluation of the reconstruction of image acquired from CT simulator to reduce metal artifact

International Nuclear Information System (INIS)

Choi, Ji Hun; Park, Jin Hong; Choi, Byung Don; Won, Hui Su; Chang, Nam Jun; Goo, Jang Hyun; Hong, Joo Wan

2014-01-01

This study presents the usefulness assessment of metal artifact reduction for orthopedic implants(O-MAR) to decrease metal artifacts from materials with high density when acquired CT images. By CT simulator, original CT images were acquired from Gammex and Rando phantom and those phantoms inserted with high density materials were scanned for other CT images with metal artifacts and then O-MAR was applied to those images, respectively. To evaluate CT images using Gammex phantom, 5 regions of interest(ROIs) were placed at 5 organs and 3 ROIs were set up at points affected by artifacts. The averages of standard deviation(SD) and CT numbers were compared with a plan using original image. For assessment of variations in dose of tissue around materials with high density, the volume of a cylindrical shape was designed at 3 places in images acquired from Rando phantom by Eclipse. With 6 MV, 7-fields, 15x15cm 2 and 100 cGy per fraction, treatment planning was created and the mean dose were compared with a plan using original image. In the test with the Gammex phantom, CT numbers had a few difference at established points and especially 3 points affected by artifacts had most of the same figures. In the case of O-MAR image, the more reduction in SD appeared at all of 8 points than non O-MAR image. In the test using the Rando Phantom, the variations in dose of tissue around high density materials had a few difference between original CT image and CT image with O-MAR. The CT images using O-MAR were acquired clearly at the boundary of tissue around high density materials and applying O-MAR was useful for correcting CT numbers

Water on Mars: Evidence from MER Mission Results

Science.gov (United States)

Landis, Geoffrey A.

2004-01-01

The Viking and the Mars Exploration Rover missions observed that the surface of Mars is encrusted by a thinly cemented layer, or "duricrust". Elemental analyzes at five sites on Mars show that these soils have sulfur content and chlorine content consistent with the presence of sulfates and halides as mineral cements. The soil is highly enriched in the salt-forming elements compared with rock. Analysis of the soil cementation indicates some features which may be evidence of liquid water. At both MER sites, duricrust textures revealed by the Microscopic Imager show features including the presence of fine sand-sized grains, some of which may be aggregates of fine silt and clay, surrounded by a pervasive light colored material that is associated with microtubular structures and networks of microfractures. Stereo views of undisturbed duricrust surfaces reveal rugged microrelief between 2-3 mm and minimal loose material. Comparisons of microscopic images of duricrust soils obtain before and after placement of the Mossbauer spectrometer indicate differing degrees of compaction and cementation. Two models of a transient water hypothesis are offered, a "top down" hypothesis that emphasizes the surface deposition of frost, melting and downward migration of liquid water and a "bottom up" alternative that proposes the presence of interstitial ice/brine, with the upward capillary migration of liquid water. The viability of both of these models ultimately hinges on the availability of seasonally transient liquid water for brief periods.

Estimates of visibility of the surface of Venus from descent probes and balloons

Science.gov (United States)

Moroz, V. I.

2002-03-01

One of the tasks of future missions to Venus could be imaging of the surface either from a probe during its descent or from a balloon that drifts at a definite height below the main cloud deck. The undercloud atmosphere restricts capabilities of this experiment in three ways: (1) true absorption in bands of CO 2 and H 2O, (2) gaseous Rayleigh scattering, and (3) scattering and absorption by the undercloud haze. The first and second are dominant, at least below 30- 35 km. Wavelength 1.02 μm seems to be the most favorable as the centre of a window for imaging because the true (band) absorption and Rayleigh optical depth are minimal here. It is also important that this wavelength is within the range of silicon CCD spectral sensitivity. Wavelengths 0.85 and 0.65 μm are included in the analysis. A special number (the visibility factor) is introduced for the quantitative estimates of the atmospheric influence on the quality of surface images. Results of Venera 13 and 14 are used as key information about the optical properties of the atmosphere of Venus. Two cases are discussed: (1) imaging during the daytime in all three windows and (2) night imaging in 1 μm window using the thermal emission of the surface. It is shown that at daytime 3-color imaging with the use of all three windows would be difficult from heights more than a few kilometers, but in 1 μm the approximate upper limit is about 15 km. Visibility of highlands will be better. Night conditions are better for imaging: pictures in 1 μm window. Night images may have acceptable quality just after the passage of the lower boundary of the main cloud deck (48- 50 km). However, interpretation may meet difficulties due to mixing effects of temperatures and emissivity surface fields. NIR surface mapping from orbiters is possible, but it will not provide space resolution better than about 50- 100 km. This mapping will deliver information about surface temperature (linked with topography). Constraints on the mineral

The subsurface geology of Río Tinto: material examined during a simulated Mars drilling mission for the Mars Astrobiology Research and Technology Experiment (MARTE).

Science.gov (United States)

Prieto-Ballesteros, Olga; Martínez-Frías, Jesús; Schutt, John; Sutter, Brad; Heldmann, Jennifer L; Bell, Mary Sue; Battler, Melissa; Cannon, Howard; Gómez-Elvira, Javier; Stoker, Carol R

2008-10-01

The 2005 Mars Astrobiology Research and Technology Experiment (MARTE) project conducted a simulated 1-month Mars drilling mission in the Río Tinto district, Spain. Dry robotic drilling, core sampling, and biological and geological analytical technologies were collectively tested for the first time for potential use on Mars. Drilling and subsurface sampling and analytical technologies are being explored for Mars because the subsurface is the most likely place to find life on Mars. The objectives of this work are to describe drilling, sampling, and analytical procedures; present the geological analysis of core and borehole material; and examine lessons learned from the drilling simulation. Drilling occurred at an undisclosed location, causing the science team to rely only on mission data for geological and biological interpretations. Core and borehole imaging was used for micromorphological analysis of rock, targeting rock for biological analysis, and making decisions regarding the next day's drilling operations. Drilling reached 606 cm depth into poorly consolidated gossan that allowed only 35% of core recovery and contributed to borehole wall failure during drilling. Core material containing any indication of biology was sampled and analyzed in more detail for its confirmation. Despite the poorly consolidated nature of the subsurface gossan, dry drilling was able to retrieve useful core material for geological and biological analysis. Lessons learned from this drilling simulation can guide the development of dry drilling and subsurface geological and biological analytical technologies for future Mars drilling missions.

Moon/Mars Landing Commemorative Release: Gusev Crater and Ma'adim Vallis

Science.gov (United States)

1998-01-01

the mouth of Ma'adim Vallis--are composed of sediment that eroded out of the highlands to the south of Gusev Crater. In 1995, the Exobiology Program Office at NASA Headquarters produced a report, An Exobiological Strategy for Mars Exploration (NASA SP-530), that included Gusev Crater as a possible priority site for future Mars exploration because it might once have been a lake.At 12:17 a.m. (PDT) on April 24, 1998-- during Mars Global Surveyor's 259th orbit--MOC obtained the high resolution image of Gusev Crater and Ma'adim Vallis shown above, in part to test some of the proposed hypotheses. The raw image has a scale of 7.3 meters (24 feet) per pixel. At this scale, there are no obvious shorelines that would indicate the past presence of a lake in either Ma'adim Vallis or Gusev Crater. There are several alternative explanations for this absence, including: It is possible that any lake in Gusev occurred so long ago that erosion by wind and hillslope processes have long since removed such features. It is possible that 7.3 meters per pixel is insufficient to identify key diagnostic lake features. It is possible that a lake once existed, but that shore- and near-shore processes as they occur in terrestrial lake environments did not occur on Mars. It is possible no lake ever existed. When Mars Global Surveyor achieves its Mapping Orbit in March 1999, MOC will have the ability to obtain pictures with resolutions around 1.5 meters (5 feet) per pixel. Sometime during the mapping mission, it may be possible to image Gusev Crater again to look for potential lake features and possible future landing sites.Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from

Mars Navigator: An Interactive Multimedia Program about Mars, Aerospace Engineering, Astronomy, and the JPL Mars Missions. [CD-ROM

Science.gov (United States)

Gramoll, Kurt

This CD-ROM introduces basic astronomy and aerospace engineering by examining the Jet Propulsion Laboratory's (JPL) Mars Pathfinder and Mars Global Surveyor missions to Mars. It contains numerous animations and narrations in addition to detailed graphics and text. Six interactive laboratories are included to help understand topics such as the…

The CanMars Analogue Mission: Lessons Learned for Mars Sample Return

Science.gov (United States)

Osinski, G. R.; Beaty, D.; Battler, M.; Caudill, C.; Francis, R.; Haltigin, T.; Hipkin, V.; Pilles, E.

2018-04-01

We present an overview and lessons learned for Mars Sample Return from CanMars — an analogue mission that simulated a Mars 2020-like cache mission. Data from 39 sols of operations conducted in the Utah desert in 2015 and 2016 are presented.

Value of MRI in the diagnosis of stress urinary incontinence in the absence of organ descent

International Nuclear Information System (INIS)

Beyersdorff, D.; Taupitz, M.; Fischer, T.; Hamm, B.; Tunn, R.; Rieprich, M.

2001-01-01

To detect pathomorphological changes of the pelvic floor, the vagina, and the urethra by MR imaging in patients with stress urinary incontinence in the absence of organ descent compared with findings in 10 healthy controls. Materials and Methods: The study included 10 healthy controls and 38 patients with stage II urinary incontinence showing no urge symptoms but a pathological stress profile on urodynamic testing. The subjects underwent MR imaging with a phased-array coil at 1.5 T in addition to urodynamic testing and gynecological examination. The following sequences were used: axial and coronal PD-weighted TSE sequences with a FOV of 20 cm and a section thickness of 4 mm; axial STIR sequence. Sagittal T 2 -weighted HASTE sequences were acquired during pelvic floor contraction, relaxation, and straining maneuvers. Results: In 22/38 cases pathomorphological changes were found by MR imaging. The pathomorphological changes were classified as lateral defects (n = 14) if the musculofascial connection between the levator muscle and the lateral vaginal wall or the butterfly shape of the vagina was absent and as central (n = 16) if changes were detected in the urethral wall. Defects of the pelvic floor muscles were detected in 8 cases. No underlying changes were identified in 16/38 cases. Conclusion: In cases of female urinary incontinence, MR imaging of the pelvic floor can detect pathomorphological changes, which are difficult to identify by clinical examination. MR imaging currently does not allow the detection of morphological changes in all forms of female urinary stress incontinence. (orig.) [de

'The full has never been told': building a theory of sexual health for heterosexual Black men of Caribbean descent.

Science.gov (United States)

Crowell, Candice N; Delgado-Romero, Edward A; Mosley, Della V; Huynh, Sophia

2016-08-01

Research on Black sexual health often fails to represent the heterogeneity of Black ethnic groups. For people of Caribbean descent in the USA, ethnicity is a salient cultural factor that influences definitions and experiences of sexual health. Most research on people of Caribbean descent focuses on the relatively high rate of STIs, but sexual health is defined more broadly than STI prevalence. Psychological and emotional indicators and the voice of participants are important to consider when exploring the sexual health of a minority culture. The purpose of this study was to qualitatively explore how heterosexual Black men of Caribbean descent define and understand sexual health for themselves. Eleven men who self-identified as Black, Caribbean and heterosexual participated in three focus groups and were asked to define sexual health, critique behaviours expertly identified as healthy and address what encourages and discourages sexual health in their lives. Findings point to six dimensions of sexual health for heterosexual Black men of Caribbean descent. These include: heterosexually privileged, protective, contextual, interpersonal, cultural and pleasurable dimensions. There were some notable departures from current expert definitions of sexual health. Recommendations for further theory development are provided.

Hardened Lava Meets Wind on Mars

Science.gov (United States)

2006-01-01

NASA's Mars Exploration Rover Spirit used its microscopic imager to capture this spectacular, jagged mini-landscape on a rock called 'GongGong.' Measuring only 3 centimeters (1.2 inches) across, this surface records two of the most important and violent forces in the history of Mars -- volcanoes and wind. GongGong formed billions of years ago in a seething, stirring mass of molten rock. It captured bubbles of gases that were trapped at great depth but had separated from the main body of lava as it rose to the surface. Like taffy being stretched and tumbled, the molten rock was deformed as it moved across an ancient Martian landscape. The tiny bubbles of gas were deformed as well, becoming elongated. When the molten lava solidified, the rock looked like a frozen sponge. Far from finished with its life, the rock then withstood billions of years of pelting by small sand grains carried by Martian dust storms that sometimes blanketed the planet. The sand wore away the surface until, little by little, the delicate strands that enclosed the bubbles of gas were breached and the spiny texture we see today emerged. Even now, wind continues to deposit sand and dust in the holes and crevices of the rock. Similar rocks can be found on Earth where the same complex interplay of volcanoes and weathering occur, whether it be the pelting of rocks by sand grains in the Mojave desert or by ice crystals in the frigid Antarctic. GongGong is one of a group of rocks studied by Spirit and informally named by the Athena Science Team to honor the Chinese New Year (the Year of the Dog). In Chinese mythology, GongGong was the god-king of water in the North Land. When he sacrificed his life to knock down Mount BuZhou, he defeated the bad Emperor in Heaven, freed the sun, moon and stars to go from east to west, and caused all the rivers in China to flow from west to east. Spirit's microscopic imager took this image during on the rover's 736th day, or sol, of exploring Mars (Jan. 28, 2006). The

The DREAMS experiment flown on the ExoMars 2016 mission for the study of Martian environment during the dust storm season

Science.gov (United States)

Bettanini, C.; Esposito, R.; Debei, S.; Molfese, C.; Colombatti, G.; Aboudan, A.; Brucato, J. R.; Cortecchia, F.; Di Achille, G.; Guizzo, G. P.; Friso, E.; Ferri, F.; Marty, L.; Mennella, V.; Molinaro, R.; Schipani, P.; Silvestro, S.; Mugnuolo, R.; Pirrotta, S.; Marchetti, E.; Harri, A.-M.; Montmessin, F.; Wilson, C.; Arruego Rodriguez, I.; Abbaki, S.; Apestigue, V.; Bellucci, G.; Berthelier, J. J.; Calcutt, S. B.; Forget, F.; Genzer, M.; Gilbert, P.; Haukka, H.; Jimenez, J. J.; Jimenez, S.; Josset, J. L.; Karatekin, O.; Landis, G.; Lorenz, R.; Martinez, J.; Möhlmann, D.; Moirin, D.; Palomba, E.; Pateli, M.; Pommereau, J.-P.; Popa, C. I.; Rafkin, S.; Rannou, P.; Renno, N. O.; Schmidt, W.; Simoes, F.; Spiga, A.; Valero, F.; Vazquez, L.; Vivat, F.; Witasse, O.

2017-08-01

The DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) experiment on Schiaparelli lander of ExoMars 2016 mission was an autonomous meteorological station designed to completely characterize the Martian atmosphere on surface, acquiring data not only on temperature, pressure, humidity, wind speed and direction, but also on solar irradiance, dust opacity and atmospheric electrification, to measure for the first time key parameters linked to hazard conditions for future manned explorations. Although with very limited mass and energy resources, DREAMS would be able to operate autonomously for at least two Martian days (sols) after landing in a very harsh environment as it was supposed to land on Mars during the dust storm season (October 2016 in Meridiani Planum) relying on its own power supply. ExoMars mission was successfully launched on 14th March 2016 and Schiaparelli entered the Mars atmosphere on October 20th beginning its 'six minutes of terror' journey to the surface. Unfortunately, some unexpected behavior during the parachuted descent caused an unrecoverable critical condition in navigation system of the lander driving to a destructive crash on the surface. The adverse sequence of events at 4 km altitude triggered the transition of the lander in surface operative mode, commanding switch on the DREAMS instrument, which was therefore able to correctly power on and send back housekeeping data. This proved the nominal performance of all DREAMS hardware before touchdown demonstrating the highest TRL of the unit for future missions. This paper describes this experiment in terms of scientific goals, design, performances, testing and operational capabilities with an overview of in flight performances and available mission data.

Habitability of the Shallow Subsurface on Mars: Clues from the Meteorites

Science.gov (United States)

McKay, David S.; Wentworth, Susan J.; Thomas-Keprta, Kathie L.; Clemett, Simon; Gibson, Everett K.

2004-01-01

The properties that define habitability are commonly understood to include the following: Presence of water. Temperature range allowing some or all of the water to be liquid. A suitable physical volume or space permitting metabolism and growth. Presence of organic compounds or the building blocks to make them. Presence of an energy source suitable for utilization by living organisms. Interpretations of Mars Viking, Surveyor, and Odyssey orbital images have built a strong case that Mars had surface water during its past geological history. Neutron spectrometer data from Mars Odyssey show that poleward of about 60 degrees North and 60 degrees south, significant hydrogen, likely as ice or permafrost, is present in at least the upper meter or so of the martian regolith and crust and that similar high hydrogen areas exist, even near the equator. Here we present a summary of independent data from the Mars meteorites showing that liquid water was present for at least some of the time in the upper few meters or tens of meters as early as 3.9 billion years (Ga), and was present at intervals and at various locations throughout most of Mars history.

Secular Climate Change on Mars: An Update Using One Mars Year of MSL Pressure Data

Science.gov (United States)

Haberle, R. M.; Gomez-Elvira, J.; de la Torre Juarez, M.; Harri, A-M.; Hollingsworth, J. L.; Kahanpaa, H.; Kahre, M. A.; Lemmon, M.; Martin-Torres, F. J.; Mischna, M.;

Adaptive ISAR Imaging of Maneuvering Targets Based on a Modified Fourier Transform.

Science.gov (United States)

Wang, Binbin; Xu, Shiyou; Wu, Wenzhen; Hu, Pengjiang; Chen, Zengping

2018-04-27

Focusing on the inverse synthetic aperture radar (ISAR) imaging of maneuvering targets, this paper presents a new imaging method which works well when the target's maneuvering is not too severe. After translational motion compensation, we describe the equivalent rotation of maneuvering targets by two variables-the relative chirp rate of the linear frequency modulated (LFM) signal and the Doppler focus shift. The first variable indicates the target's motion status, and the second one represents the possible residual error of the translational motion compensation. With them, a modified Fourier transform matrix is constructed and then used for cross-range compression. Consequently, the imaging of maneuvering is converted into a two-dimensional parameter optimization problem in which a stable and clear ISAR image is guaranteed. A gradient descent optimization scheme is employed to obtain the accurate relative chirp rate and Doppler focus shift. Moreover, we designed an efficient and robust initialization process for the gradient descent method, thus, the well-focused ISAR images of maneuvering targets can be achieved adaptively. Human intervention is not needed, and it is quite convenient for practical ISAR imaging systems. Compared to precedent imaging methods, the new method achieves better imaging quality under reasonable computational cost. Simulation results are provided to validate the effectiveness and advantages of the proposed method.

An ordinary camera in an extraordinary location: Outreach with the Mars Webcam

Science.gov (United States)

Ormston, T.; Denis, M.; Scuka, D.; Griebel, H.

2011-09-01

The European Space Agency's Mars Express mission was launched in 2003 and was Europe's first mission to Mars. On-board was a small camera designed to provide ‘visual telemetry’ of the separation of the Beagle-2 lander. After achieving its goal it was shut down while the primary science mission of Mars Express got underway. In 2007 this camera was reactivated by the flight control team of Mars Express for the purpose of providing public education and outreach—turning it into the ‘Mars Webcam’.The camera is a small, 640×480 pixel colour CMOS camera with a wide-angle 30°×40° field of view. This makes it very similar in almost every way to the average home PC webcam. The major difference is that this webcam is not in an average location but is instead in orbit around Mars. On a strict basis of non-interference with the primary science activities, the camera is turned on to provide unique wide-angle views of the planet below.A highly automated process ensures that the observations are scheduled on the spacecraft and then uploaded to the internet as rapidly as possible. There is no intermediate stage, so that visitors to the Mars Webcam blog serve as ‘citizen scientists’. Full raw datasets and processing instructions are provided along with a mechanism to allow visitors to comment on the blog. Members of the public are encouraged to use this in either a personal or an educational context and work with the images. We then take their excellent work and showcase it back on the blog. We even apply techniques developed by them to improve the data and webcam experience for others.The accessibility and simplicity of the images also makes the data ideal for educational use, especially as educational projects can then be showcased on the site as inspiration for others. The oft-neglected target audience of space enthusiasts is also important as this allows them to participate as part of an interplanetary instrument team.This paper will cover the history of the

Magnetic resonance imaging of pelvic floor dysfunction.

Science.gov (United States)

Lalwani, Neeraj; Moshiri, Mariam; Lee, Jean H; Bhargava, Puneet; Dighe, Manjiri K

2013-11-01

Pelvic floor dysfunction is largely a complex problem of multiparous and postmenopausal women and is associated with pelvic floor or organ descent. Physical examination can underestimate the extent of the dysfunction and misdiagnose the disorders. Functional magnetic resonance (MR) imaging is emerging as a promising tool to evaluate the dynamics of the pelvic floor and use for surgical triage and operative planning. This article reviews the anatomy and pathology of pelvic floor dysfunction, typical imaging findings, and the current role of functional MR imaging. Copyright © 2013 Elsevier Inc. All rights reserved.

Metal artifact reduction image reconstruction algorithm for CT of implanted metal orthopedic devices: a work in progress

International Nuclear Information System (INIS)

Liu, Patrick T.; Pavlicek, William P.; Peter, Mary B.; Roberts, Catherine C.; Paden, Robert G.; Spangehl, Mark J.

2009-01-01

Despite recent advances in CT technology, metal orthopedic implants continue to cause significant artifacts on many CT exams, often obscuring diagnostic information. We performed this prospective study to evaluate the effectiveness of an experimental metal artifact reduction (MAR) image reconstruction program for CT. We examined image quality on CT exams performed in patients with hip arthroplasties as well as other types of implanted metal orthopedic devices. The exam raw data were reconstructed using two different methods, the standard filtered backprojection (FBP) program and the MAR program. Images were evaluated for quality of the metal-cement-bone interfaces, trabeculae ≤1 cm from the metal, trabeculae 5 cm apart from the metal, streak artifact, and overall soft tissue detail. The Wilcoxon Rank Sum test was used to compare the image scores from the large and small prostheses. Interobserver agreement was calculated. When all patients were grouped together, the MAR images showed mild to moderate improvement over the FBP images. However, when the cases were divided by implant size, the MAR images consistently received higher image quality scores than the FBP images for large metal implants (total hip prostheses). For small metal implants (screws, plates, staples), conversely, the MAR images received lower image quality scores than the FBP images due to blurring artifact. The difference of image scores for the large and small implants was significant (p=0.002). Interobserver agreement was found to be high for all measures of image quality (k>0.9). The experimental MAR reconstruction algorithm significantly improved CT image quality for patients with large metal implants. However, the MAR algorithm introduced blurring artifact that reduced image quality with small metal implants. (orig.)

Cardiovascular disease, diabetes and established risk factors among populations of sub-Saharan African descent in Europe: a literature review

Directory of Open Access Journals (Sweden)

de Graft Aikins Ama

2009-08-01

Full Text Available Abstract Background Most European countries are ethnically and culturally diverse. Globally, cardiovascular disease (CVD is the leading cause of death. The major risk factors for CVD have been well established. This picture holds true for all regions of the world and in different ethnic groups. However, the prevalence of CVD and related risk factors vary among ethnic groups. Methods This article provides a review of current understanding of the epidemiology of vascular disease, principally coronary heart disease (CHD, stroke and related risk factors among populations of Sub-Sahara African descent (henceforth, African descent in comparison with the European populations in Europe. Results Compared with European populations, populations of African descent have an increased risk of stroke, whereas CHD is less common. They also have higher rates of hypertension and diabetes than European populations. Obesity is highly prevalent, but smoking rate is lower among African descent women. Older people of African descent have more favourable lipid profile and dietary habits than their European counterparts. Alcohol consumption is less common among populations of African descent. The rate of physical activity differs between European countries. Dutch African-Suriname men and women are less physically active than the White-Dutch whereas British African women are more physically active than women in the general population. Literature on psychosocial stress shows inconsistent results. Conclusion Hypertension and diabetes are highly prevalent among African populations, which may explain their high rate of stroke in Europe. The relatively low rate of CHD may be explained by the low rates of other risk factors including a more favourable lipid profile and the low prevalence of smoking. The risk factors are changing, and on the whole, getting worse especially among African women. Cohort studies and clinical trials are therefore needed among these groups to

Distributed Coordinate Descent Method for Learning with Big Data

OpenAIRE

Richtárik, Peter; Takáč, Martin

2013-01-01

In this paper we develop and analyze Hydra: HYbriD cooRdinAte descent method for solving loss minimization problems with big data. We initially partition the coordinates (features) and assign each partition to a different node of a cluster. At every iteration, each node picks a random subset of the coordinates from those it owns, independently from the other computers, and in parallel computes and applies updates to the selected coordinates based on a simple closed-form formula. We give bound...

Periprosthetic Artifact Reduction Using Virtual Monochromatic Imaging Derived From Gemstone Dual-Energy Computed Tomography and Dedicated Software.

Science.gov (United States)

Reynoso, Exequiel; Capunay, Carlos; Rasumoff, Alejandro; Vallejos, Javier; Carpio, Jimena; Lago, Karen; Carrascosa, Patricia

2016-01-01

The aim of this study was to explore the usefulness of combined virtual monochromatic imaging and metal artifact reduction software (MARS) for the evaluation of musculoskeletal periprosthetic tissue. Measurements were performed in periprosthetic and remote regions in 80 patients using a high-definition scanner. Polychromatic images with and without MARS and virtual monochromatic images were obtained. Periprosthetic polychromatic imaging (PI) showed significant differences compared with remote areas among the 3 tissues explored (P remote tissues using monochromatic imaging with MARS (P = 0.053 bone, P = 0.32 soft tissue, and P = 0.13 fat). However, such differences were significant using PI with MARS among bone (P = 0.005) and fat (P = 0.02) tissues. All periprosthetic areas were noninterpretable using PI, compared with 11 (9%) using monochromatic imaging. The combined use of virtual monochromatic imaging and MARS reduced periprosthetic artifacts, achieving attenuation levels comparable to implant-free tissue.

Extratropical Weather Systems on Mars: Radiatively-Active Water Ice Effects

Science.gov (United States)

Hollingsworth, J. L.; Kahre, M. A.; Haberle, R. M.; Urata, R. A.; Montmessin, F.

2017-01-01

Extratropical, large-scale weather disturbances, namely transient, synoptic-period,baroclinic barotropic eddies - or - low- (high-) pressure cyclones (anticyclones), are components fundamental to global circulation patterns for rapidly rotating, differentially heated, shallow atmospheres such as Earth and Mars. Such "wave-like" disturbances that arise via (geophysical) fluid shear instability develop, mature and decay, and travel west-to-east in the middle and high latitudes within terrestrial-like planetary atmospheres. These disturbances serve as critical agents in the transport of heat and momentum between low and high latitudes of the planet. Moreover, they transport trace species within the atmosphere (e.g., water vapor/ice, other aerosols (dust), chemical species, etc). Between early autumn through early spring, middle and high latitudes on Mars exhibit strong equator-to-pole mean temperature contrasts (i.e., "baroclinicity"). Data collected during the Viking era and observations from both the Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO) indicate that such strong baroclinicity supports vigorous, large-scale eastward traveling weather systems [Banfield et al., 2004; Barnes et al., 1993]. A good example of traveling weather systems, frontal wave activity and sequestered dust activity from MGS/MOC image analyses is provided in Figure 1 (cf. Wang et al. [2005]). Utilizing an upgraded and evolving version of the NASA Ames Research Center (ARC) Mars global climate model, investigated here are key dynamical and physical aspects of simulated northern hemisphere (NH) large-scale extratropica lweather systems,with and without radiatively-active water ice clouds. Mars Climate Model:

History of Mars

International Nuclear Information System (INIS)

Lewis, J.S.

1988-01-01

The origin and early history of Mars and the relationship between Mars and the other planets are reviewed. The solar system formation and planetary differentiation are examined using data from planetary missions. Different views of Mars are presented, showing how ideas about the planet have changed as the amount of available observational data has increased. Viking aerography and surface characterization are discussed, including the nature of specific atmospheric components and the implications of surface phenomena. Models for the planetary formation and accretion processes are considered. The value of future missions to Mars is stressed

Convergence results for a class of abstract continuous descent methods

Directory of Open Access Journals (Sweden)

Sergiu Aizicovici

2004-03-01

Full Text Available We study continuous descent methods for the minimization of Lipschitzian functions defined on a general Banach space. We establish convergence theorems for those methods which are generated by approximate solutions to evolution equations governed by regular vector fields. Since the complement of the set of regular vector fields is $sigma$-porous, we conclude that our results apply to most vector fields in the sense of Baire's categories.

Rock Moved by Mars Lander Arm

Science.gov (United States)

2008-01-01

The robotic arm on NASA's Phoenix Mars Lander slid a rock out of the way during the mission's 117th Martian day (Sept. 22, 2008) to gain access to soil that had been underneath the rock.The lander's Surface Stereo Imager took the two images for this stereo view later the same day, showing the rock, called 'Headless,' after the arm pushed it about 40 centimeters (16 inches) from its previous location. 'The rock ended up exactly where we intended it to,' said Matt Robinson of NASA's Jet Propulsion Laboratory, robotic arm flight software lead for the Phoenix team. The arm had enlarged the trench near Headless two days earlier in preparation for sliding the rock into the trench. The trench was dug to about 3 centimeters (1.2 inches) deep. The ground surface between the rock's prior position and the lip of the trench had a slope of about 3 degrees downward toward the trench. Headless is about the size and shape of a VHS videotape. The Phoenix science team sought to move the rock in order to study the soil and the depth to subsurface ice underneath where the rock had been. This image was taken at about 12:30 p.m., local solar time on Mars. The view is to the north northeast of the lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

Cardiac magnetic resonance imaging

African Journals Online (AJOL)

2011-03-06

Mar 6, 2011 ... Cardiac magnetic resonance imaging. Cardiovascular magnetic resonance imaging is becoming a routine diagnostic technique. BRUCE s sPOTTiswOOdE, PhD. MRC/UCT Medical Imaging Research Unit, University of Cape Town, and Division of Radiology, Stellenbosch University. Bruce Spottiswoode ...

Mars Mapping Technology Brings Main Street to Life

Science.gov (United States)

2008-01-01

The Red Planet has long held a particular hold on the human psyche. From the Roman god of war to Orson Welles infamous Halloween broadcast, our nearest planetary neighbor has been viewed with curiosity, suspicion, and awe. Pictures of Mars from 1965 to the present reveal familiar landscapes while also challenging our perceptions and revising our understanding of the processes at work in planets. Frequent discoveries have forced significant revisions to previous theories. Although Mars shares many familiar features with Earth, such as mountains, plains, valleys, and polar ice, the conditions on Mars can vary wildly from those with which we are familiar. The apparently cold, rocky, and dusty wasteland seen through the eyes of spacecraft and Martian probes hints at a dynamic past of volcanic activity, cataclysmic meteors, and raging waters. New discoveries continue to revise our view of our next-door neighbor, and further exploration is now paving the way for a human sortie to the fourth stone from the Sun. NASA s Mars Exploration Program, a long-term effort of robotic exploration, utilizes wide-angle stereo cameras mounted on NASA s twin robot geologists, the Mars Exploration Rovers (MERs), launched in 2003. The rovers, named "Spirit" and "Opportunity," celebrated 4 Earth years of exploration on January 3, 2008, and have sent back a wealth of information on the terrain and composition of the Martian surface. Their marathon performance has far outlasted the intended 90 days of operation, and the two intrepid explorers promise more images and data.

Physical properties of the martian surface from the Viking 1 lander: preliminary results

International Nuclear Information System (INIS)