In early 2011, NASA's Mars Exploration Rover (MER) Opportunity began experiencing intermittent errors when writing data products to Flash memory. Similar errors occurred with increasing frequency in early 2013 and many were accompanied by unexpected resets of the rover's flight computer (warm reboots). Depending on timing, warm reboots occasionally caused communication faults. Although these errors subsided in mid-2013, they returned at an increasing rate in mid-2014. The MER team developed techniques to mitigate the effects of infrequent warm reboots but these became ineffective as the rate and severity of the errors increased. Faced with these more frequent errors, the MER team decided to reformat the Flash memory. Using lessons learned from reformatting the Flash file system on the Spirit rover and implementing some new techniques, the MER team was able to reformat Flash and resume science operations much more quickly than anticipated. This paper will discuss the history of Flash related anomalies, suspect cause, initial operational mitigations, and the ultimate Flash reformat strategy and rover recovery activities.

This paper presents the development, validation, and deployment of the visual target tracking capability onto the Mars Exploration Rover (MER) mission. Visual target tracking enables targeted driving, in which the rover approaches a designated target in a closed visual feedback loop, increasing the target position accuracy by an order of magnitude and resulting in fewer ground-in-the-loop cycles. As a result of an extensive validation, we developed a reliable normalized cross-correlation visual tracker. To enable tracking with the limited computational resources of a planetary rover, the tracker uses the vehicle motion estimation to scale and roll the template image, compensating for large image changes between rover steps. The validation showed that a designated target can be reliably tracked within several pixels or a few centimeters of accuracy over a 10-m traverse using a rover step size of 10% of the target distance in any direction. It also showed that the target is not required to have conspicuous features and can be selected anywhere on natural rock surfaces excluding rock boundary and shadowed regions. The tracker was successfully executed on the Opportunity rover near Victoria Crater on four distinct runs, including a single-sol instrument placement. We present the flight experiment data of the tracking performance and execution time. © 2009 Wiley Periodicals, Inc.

(51) Int. C1.7 ................................................ G05B 15/00 (52) U.S. C1. ....................... 700/260; 7001245; 7001248; 7001257; 7001262; 7001263; 901127; 901128; 901130; 901134; 901136; 6001595; 6011130; 341120; 3451157; 3451161 (58) Field of Search ................................. 7001245, 248, 7001257, 260, 262, 263; 901127, 28, 30, 34, 36; 6001595; 6061130; 341120; 3451157, 161

A team of JPL researchers has analyzed stereoscopic vision software and produced a document describing its performance. This software is of the type used in maneuvering exploratory robotic vehicles on Martian terrain. The software in question utilizes correlations between portions of the images recorded by two electronic cameras to compute stereoscopic disparities, which, in conjunction with camera models, are used in computing distances to terrain points to be included in constructing a three-dimensional model of the terrain. The analysis included effects of correlation- window size, a pyramidal image down-sampling scheme, vertical misalignment, focus, maximum disparity, stereo baseline, and range ripples. Contributions of sub-pixel interpolation, vertical misalignment, and foreshortening to stereo correlation error were examined theoretically and experimentally. It was found that camera-calibration inaccuracy contributes to both down-range and cross-range error but stereo correlation error affects only the down-range error. Experimental data for quantifying the stereo disparity error were obtained by use of reflective metrological targets taped to corners of bricks placed at known positions relative to the cameras. For the particular 1,024-by-768-pixel cameras of the system analyzed, the standard deviation of the down-range disparity error was found to be 0.32 pixel.

A paper describes a method devised to increase the robustness and accuracy of tracking of targets by means of three stereoscopic pairs of video cameras on a Mars-rover-type exploratory robotic vehicle. Two of the camera pairs are mounted on a mast that can be adjusted in pan and tilt; the third camera pair is mounted on the main vehicle body. Elements of the method include a mast calibration, a camera-pointing algorithm, and a purely geometric technique for handing off tracking between different camera pairs at critical distances as the rover approaches a target of interest. The mast calibration is an extension of camera calibration in which the camera images of calibration targets at known positions are collected at various pan and tilt angles. In the camerapointing algorithm, pan and tilt angles are computed by a closed-form, non-iterative solution of inverse kinematics of the mast combined with mathematical models of the cameras. The purely geometric camera-handoff technique involves the use of stereoscopic views of a target of interest in conjunction with the mast calibration.

This paper presents three technical elements that we have developed to improve the accuracy of the visual target tracking for single-sol approach-and-instrument placement in future Mars rover missions. An accurate, straightforward method of rover mast calibration is achieved by using a total station, a camera calibration target, and four prism targets mounted on the rover. The method was applied to Rocky8 rover mast calibration and yielded a 1.1-pixel rms residual error. Camera pointing requires inverse kinematic solutions for mast pan and tilt angles such that the target image appears right at the center of the camera image. Two issues were raised. Mast camera frames are in general not parallel to the masthead base frame. Further, the optical axis of the camera model in general does not pass through the center of the image. Despite these issues, we managed to derive non-iterative closed-form exact solutions, which were verified with Matlab routines. Actual camera pointing experiments over 50 random target image points yielded less than 1.3-pixel rms pointing error. Finally, a purely geometric method for camera handoff using stereo views of the target has been developed. Experimental test runs show less than 2.5 pixels error on high-resolution Navcam for Pancam-to-Navcam handoff, and less than 4 pixels error on lower-resolution Hazcam for Navcam-to-Hazcam handoff

This paper presents an in-depth performance analysis and validation of a correlation based stereo vision system being used as part of the ongoing 2003 Mars Exploration Rover flight mission. Our analysis includes the effects of correlation window size, pyramidal image down-sampling, vertical misalignment, focus, maximum disparity, stereo baseline, and range ripples. A key element of validation is to determine the stereo localization error both analytically and experimentally. We study both down-range and cross-range error and verify that while camera calibration inaccuracy contributes to both, stereo correlation error affects only the former. Error contributions of subpixel interpolation, vertical misalignment, and foreshortening on stereo correlation are examined carefully. A novel method using bricks with reflective metrology targets and a mast-mounted stereo camera system enabled experimental measurements of the stereo disparity error. The standard deviation of the down-range disparity error was measured at sigma=0.32 pixel for high-resolution 1024times768 camera images. The result is critical in evaluating accurate rover navigation and instrument placement within given error budgets

The Mars Exploration Rovers (MER'03), Spirit and Opportunity, represent the state of the art in rover operations on Mars. This paper presents validation experiments of different visual tracking algorithms using the rover's navigation camera.

A telerobotic platform developed in a collaboration between NASA-JPL and MicroDexterity Systems, Inc (MDS) is described in this paper. The lightweight, compact 6 dof master-slave system is precise to better than 10 microns and can cover a workspace greater than 400 cubic centimeters. Current capabilities of the system include manual position control with augmented shared control modes and automatic modes of control of the robot. Simulated force feedback on the master device has been implemented and plans are to integrate force reflection from the slave end effector and evaluate the performance improvements enabled by the telerobot in simulated microsurgical tasks. The telerobot was used in a recent demonstration of a simulated eye microsurgical procedure.

A telerobotic workstation for microsurgery has been developed that enables scaling down motions and filtering tremor in a surgeon's hand. The system is compact and light-weight and has the potential for improving the performance of all surgeons and enabling the development of new surgical procedures currently limited by the dexterity of even the most skilful surgeons.

Alvin and Heidi Toffler have eloquently articulated the importance of information as a substitute for time, space, capital and labor—and indeed as a proxy for violence. In the information age, only "smart nations" will be able to provide for the common defense, and only "smart nations" will be economically competitive and able to assure the prosperity of their citizens. Individual information specialists in the private sector—what Robert Carkhuff has called the gold collar worker—now comprise the armies of the future and also the spies of the future; it is the private sector information specialist who will bear arms, collect and produce intelligence, and generally be the foundation for creating the "smart nation." Information warfare or IW is now very much in fashion, but as with so many other fads in American history, it is focused almost exclusively on developing enormously complex electronic architectures and on offensive attacks against others (many of whom do not have significant electronic infrastructures susceptible to electronic attack). The current emphasis appears to achieve a patina of comprehensiveness through its variation of technique—one can talk of hard kills with physical means versus soft kills with electronic means; of irreversible damage versus reversible damage; of detectable versus undetectable impact; and finally of one-time versus sporadic or repetitive attack and impact. In fact this focus is severely limited. Consider instead a larger concept, in which there are three critical aspects to waging war and keeping the peace in cyberspace: first and foremost, and completely ignored by most warriors, is the importance of intelligence—of knowing the environment, the enemy and the other players in depth so as to make informed judgments. In this area, open source intelligence—public information readily available to information professionals, comprises the bulk of the raw material. Second is electronic home defense. Finally, and least important in the overall scheme of things, is offensive information warfare. Missing completely from this equation, but perhaps occupying the entire inner space of the triangle formed by these three elements, is information peace-keeping. These four elements of national defense and national competitiveness in the age of information—intelligence, electronic home defense, offensive information warfare and information peacekeeping—cannot be defined, established or managed in a vacuum. We urgently need a national information strategy which provides four pillars for meeting our varying needs in these areas: the pillar of connectivity or assured access; the pillar of content or networked distributed centers of expertise; the pillar of coordination to avoid wasted resources and enhance interoperability; and finally the pillar of communications and computing security, making it safe for all Americans to work and play in cyberspace. As we contemplate our present and our future, we cannot help but note that we face five revolutions, which I call the challenges of change. The first revolution is the dramatic increase in the complexity of the threat and the power of single individuals and small gangs to do great damage to the financial, power, communications and transportation infrastructure of the United States of America. Neither our Department of Defense nor our U.S. intelligence community is organized to address these new threats, and our local and even our national law enforcement bodies are overwhelmed and inadequately funded for this transnational threat. At the same time, in a second revolution of changing demands, we see the Secretary of State properly declaring that the global environment is a national security issue; we see various forms of cultural and economic migrations, many inspired by stark terror imposed from drooling Third World thugs claiming the legitimacy of a uniform; and we see "war by other means"—deliberate industrial espionage and sustained electronic crime campaigns—undertaken against the United States of America not just by traditional enemies, but by citizens of its own allies, including Canada and Israel. The third revolution is one of decline—a decline of people, platforms (vehicles to transport and protect military and law enforcement personnel) and of course a decline of dollars. We are being asked to do more with less, but we have not figured out in the U.S. government, as yet, how to substitute information for people, platforms and dollars. The fourth revolution is that of the changing knowledge terrain, with the global information explosion, and the emergence of smart non-state actors with more disposable power than most small nations. Finally the fifth revolution, changing technology, has placed in the hands of rogue nations, as well as terrorists and criminals, vast arrays of extremely powerful yet inexpensive and easily concealable information warfare tools. Now then, in the face of these challenges, we are confronted with the urgent need to reinvent our approach to national security and to national competitiveness. As we consider trends in information warfare and open source intelligence, we quickly come to the realization that the two are related, and that a national information strategy is the umbrella under which we can optimize our resources and create a "smart nation." In the age of information, each nation must not only be "smart," but it must mobilize all of its intellectual capital, i.e., all of its citizens and resident aliens, for total war. Only by mobilizing for total war can a total peace be reasonably achieved. Electronic security and counterintelligence, now finally established by the President as the domain of the Federal Bureau of Investigation—something I proposed in 1994 — must become a national priority. The threat must be declassified and the kinds of encryption and other tools for the protection of intellectual property released into the private sector. Legislative initiatives are necessary in order to establish "due diligence" standards for the communications and computing industry, such that consumers can rely on secure communications pathways and computer products that are not infected—as 500 were found to be infected by one organization in one year—when delivered shrink-wrapped from the factory. Open source intelligence or OSINT is now much in vogue after four years of global educational efforts on my part, but the reality is, as one Central Intelligence Agency person admitted a few weeks ago, "we have a working group, but no one is really doing anything." Worse, the beltway bandits have found that by claiming to do open source intelligence, but in fact by simply recycling their existing people and limited in-house libraries, they can win large contracts and muddle through without actually doing any serious international multilingual research. We are all losers when both our government and their major contractors fake it, but this is tantamount to abject surrender without a fight. We have an information commons in this nation, and it unfortunately bears more of a resemblance to a large garbage pit than to a healthy field of dreams. Between outrageous and well-orchestrated campaigns to steal intellectual property, and the costs of maintaining adequate security while providing public access, we have encouraged the creation of an archipelago of isolated information resources which do not contribute significantly to the national intellectual foundation. At the same time, we have one of the finest, deepest and most skilled range of individuals and organizations which comprise our national information continuum—our schools, universities, libraries, businesses, information brokers, media, government, defense and intelligence organizations are the world's best. Unfortunately, we have iron curtains between each of these nine sectors; bamboo curtains between each organization in each sector; and plastic curtains—generally hard to use technology or dumb rules— between individuals within organizations. Our national security and our national competitiveness in the 21st century will depend on our ability to clean up and nurture our information commons and our ability to break down the barriers within our information continuum so as to be able to harness—as the Vice President has taken to saying—the distributed intelligence of the nation. Elsewhere I have documented at length the new rules of the game and how one must practice intelligence in the age of information, but here five aspects of our information battlefield must be summarized: First, distributed information is far superior and more viable, as well as less expensive, that centralized information. In the age of distributed information, the concept of central intelligence is an oxymoron. The acme of skill is the seeking out of "just enough" information "just in time," and doing so through the harnessing of world-class experts whose lifetime of expertise has been developed at someone else's expense. Second, the fascination with the Internet is premature and dangerous. Eighty per cent of the information needed to properly create open source intelligence or decision-support products is either unpublished or in hard copy, in a foreign language and somewhere else. None of our intelligence or information organizations are truly structured to deal with this reality. Third, the center of gravity for national intelligence is in the civil sector, but we persist in spending billions for classified imagery and signals satellites and hundreds of thousands for a few token contracts with academics and business experts. We must radically realign the balance of spending between classified and unclassified research, and this is nowhere more apparent than in the grotesque mismatch between what we spend on national classified imagery versus what we spend for commercial imagery. Fourth, we must change our information work process and move away from the traditional linear paradigm, where the consumer goes to the analyst who goes to the collector who goes to the source—only to have the source read open source literature, concoct a third cousin with special access and back up the chain it goes, only now it is either classified or labeled corporate confidential. The new paradigm is the diamond paradigm, in which all four of these parties will talk to one another at any given time, and the acme of skill for the analyst will be the ability to put a consumer with a question in touch with an expert source who can create a tailored response in real time. Fifth, we must recognize the radical change that all this implies for the analyst. Instead of the traditional introvert, isolated with lifeless information media and producing erudite products that are thrown over the wall to a faceless customer, each analyst must become an extrovert and work diligently to manage overt networks of international human experts; networks of consumers and their staffs; and finally—such a radical notion—real money with which to hire international experts one day at a time. The private sector, not the government and not the military, is the center of gravity for both information warfare and open source intelligence. It is the private sector which has the most to lose, and the most to gain, from developing and implementing a national information strategy which can bring coherence and direction to our now fragmented and often fictitious capabilities in the information warfare and national intelligence arenas. Only by recognizing the urgency of this need, and by recognizing that the next war will be won or lost here at home, in a violent peace, very quickly, can we muster the commitment and the consensus for establishing a national information strategy which will make it safe for ourselvesand our children to work and play in cyberspace.

The chemotherapeutic value of methotrexate resides in its ability to perturb folate-dependent one-carbon metabolism and subsequently inhibit DNA synthesis. To assess the functional effect of methotrexate on hepatic one-carbon metabolism, we have developed and applied tracer kinetic techniques in vivo to quantify the carbon flux through the folate-dependent one-carbon pool in rats. Following a 7-day treatment period with methotrexate (0.2 mg/kg body weight), the tracers L-[ring-2-14C] histidine and L-[methyl-3H] methionine were simultaneously infused into control and methotrexate-treated rats. Methotrexate treatment decreased hepatic tetrahydrofolate, methyltetrahydrofolate, and formyltetrahydrofolate, concentrations by 63, 83, and 58%, respectively. Furthermore, the enzymatic activity of 10-formyltetrahydrofolate dehydrogenase, the terminal enzyme in the catabolism of the ring-2-carbon of histidine to CO2, was diminished by 32% in methotrexate-treated animals. These changes in enzyme activity and folate coenzyme concentrations did not result in a significant decrease in the oxidative flow of carbon from histidine to CO2 in methotrexate-treated rats compared to control animals (2.40 and 3.22 micromol/h/kg3/4, respectively). Oxidative carbon flow was reflective of tetrahydrofolate and formyltetrahydrofolate pools when expressed as a percent of total folate: neither coenzyme pool was diminished as a result of methotrexate treatment. In contrast, the reductive carbon flux through the one-carbon pool from histidine to methionine was significantly decreased 59% in methotrexate-treated (7.63 micromol/h/kg3/4) versus control rats (18.73 micromol/h/kg3/4)). Likewise, methyltetrahydrofolate, as a percent of total folate, was reduced 51% in methotrexate-treated rats. Consequently, total measured carbon flow (oxidative+reductive) was 54% lower in rats subjected to subchronic methotrexate treatment. These tracer kinetic experiments quantitatively demonstrate the extent to which methotrexate alters the actual carbon flow through the hepatic folate-dependent one-carbon pool, primarily directed at diminishing the reductive carbon flow towards methyltetrahydrofolate and methionine synthesis.

Cysteine sulfinic acid decarboxylase (CSAD) is a key enzyme in taurine biosynthesis. CSAD activity and enzyme protein concentration are both repressed by the action of the steroid family hormones triiodothyronine and estrogen. To characterize this suppression, a cDNA clone for CSAD was isolated from a rat liver cDNA expression library using polyclonal antibodies to CSAD. The cDNA was sequenced in its entirety and confirmed to be a clone of CSAD. In a Northern blot comparing liver and kidney RNA of male and female rats, the CSAD cDNA probe detected a 2.5 kb mRNA band which was present at levels corresponding to the concentration of enzyme protein. Hyperthyroidism decreased CSAD mRNA as compared to euthyroid controls, providing evidence that negative regulation of CSAD activity occurs at the level of mRNA.

Summary A local-remote telerobot control system is described which is being developed for time-delayed groundremote control of space telerobotic systems. The system includes a local site operator interface for interactive command building and sequencing for supervised autonomy and a remote site: the Modular Telerobot Task Execution System ( MOTES ), to provide the remote site task execution capability. The local site system also provides stereo graphics overlay on video with interactive update of the remote environmental model. The operator selects objects in the environment to interact with and skill types to specify the tasks to be performed, such as grasping a module or opening a door.

The Supervisory Telerobotics Laboratory (Steler) at the Jet Propulsion Laboratory (JPL) has developed a prototype telerobotic system to demonstrate the type of technology that will be used aboard Space Station Freedom Although the concept of telerobotics for space exploration is not new, the Steler system broke new ground in its demonstration of the feasibility of a local-remote architecture, including ground-remote control, for space applications. A remote space environment poses some interesting computational challenges to ground-remote control of space applications. A remote site has limited computation facilities, is burdened by minimal bandwidth and by round-trip communication delays of as much as 8 seconds, and yet is expected to respond quickly, predictably, and with recoverability to any anomalous situation. Additional design constraints are imposed by NASA's limitations on software, including on-board programs for the robot, being uploaded to the remote site without prior flight qualification. The authors discuss the use of Ada to meet the computational requirements of this project.<>

A telerobot task execution system that has been developed for space station Freedom applications is described. The modular telerobot task execution system (MOTES) provides the remote site task execution capability in a local-remote telerobotic system. The design addresses the constraints of limited computational power available at the remote site control system while providing a large range of control capabilities. The system provides supervised autonomous control, shared control, and teleoperation for a redundant manipulator. The system is capable of nominal task execution as well as monitoring and reflex motion. A command interpreter similar to one used on robotic spacecraft is used to interpret commands received from the local site. Execution utilizes multiple control modules which execute based upon command parameterization. The system controls a seven degree-of-freedom manipulator

The design of the remote site of a local-remote telerobot control system is described which addresses the constraints of limited computational power available at the remote site control system while providing a large range of control capabilities. The Modular Telerobot Task Execution System (MOTES) provides supervised autonomous control, shared control and teleoperation for a redundant manipulator. The system is capable of nominal task execution as well as monitoring and reflex motion. The MOTES system is minimized while providing a large capability by limiting its functionality to only that which is necessary at the remote site and by utilizing a unified multi-sensor based impedance control scheme. A command interpreter similar to one used on robotic spacecraft is used to interpret commands received from the local site. The system is written in Ada and runs in a VME environment on 68020 processors and initially controls a Robotics Research K1207 7 degree of freedom manipulator.