12 research outputs found

    XMbodyinfo

    Get PDF
    XMbodyinfo was designed to evaluate potential reference trajectories, providing a proficient way to assess the quality of all satellite body flybys for a Cassini type mission tour. It is autonomous and will generate a variety of ORS (optical remote sensing) and FPW (fields, particles, and waves) plots that aid in the evaluation, qualification, selection, and improvement of a potential tour

    Cassini Tour Atlas Automated Generation

    Get PDF
    During the Cassini spacecraft s cruise phase and nominal mission, the Cassini Science Planning Team developed and maintained an online database of geometric and timing information called the Cassini Tour Atlas. The Tour Atlas consisted of several hundreds of megabytes of EVENTS mission planning software outputs, tables, plots, and images used by mission scientists for observation planning. Each time the nominal mission trajectory was altered or tweaked, a new Tour Atlas had to be regenerated manually. In the early phases of Cassini s Equinox Mission planning, an a priori estimate suggested that mission tour designers would develop approximately 30 candidate tours within a short period of time. So that Cassini scientists could properly analyze the science opportunities in each candidate tour quickly and thoroughly so that the optimal series of orbits for science return could be selected, a separate Tour Atlas was required for each trajectory. The task of manually generating the number of trajectory analyses in the allotted time would have been impossible, so the entire task was automated using code written in five different programming languages. This software automates the generation of the Cassini Tour Atlas database. It performs with one UNIX command what previously took a day or two of human labor

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

    No full text
    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

    Automating the Generation of the Cassini Tour Atlas Database

    No full text
    The Tour Atlas is a large database of geometrical tables, plots, and graphics used by Cassini science planning engineers and scientists primarily for science observation planning. Over time, as the contents of the Tour Atlas grew, the amount of time it took to recreate the Tour Atlas similarly grew--to the point that it took one person a week of effort. When Cassini tour designers estimated that they were going to create approximately 30 candidate Extended Mission trajectories--which needed to be analyzed for science return in a short amount of time--it became a necessity to automate. We report on the automation methodology that reduced the amount of time it took one person to (re)generate a Tour Atlas from a week to, literally, one UNIX command

    The Cassini Live Update Process

    No full text
    The Cassini orbiter is an international science mission to the Saturnian system with 12 science instruments onboard. The Cassini spacecraft lacks a scan platform, which means the entire spacecraft must be rotated to control pointing of any one instrument's boresight. The resulting complex sequences of commands are built beginning many months before execution onboard. Late ephemeris updates from improved navigation data (i.e. after an orbital trim maneuver) often result in pointing commands in the sequence no longer being accurate enough to obtain the desired science observation. This paper will provide an overview of how Cassini uses live updates to address this potential loss of data, including the software developed for this process

    A modified Delphi to define drug dosing errors in pediatric critical care

    No full text
    Abstract Background There is no globally accepted definition for dosing error in adult or pediatric practice. The definition of pediatric dosing error varies greatly in the literature. The objective of this study was to develop a framework, informed by a set of principles, for a clinician-based definition of drug dosing errors in critically ill children, and to identify the range that practitioners agree is a dosing error for different drug classes and clinical scenarios. Methods We conducted a nationwide three staged modified Delphi from May to December 2019. Expert clinicians included Canadian pediatric intensive care unit (PICU) physicians, pharmacists and nurses, with a least 5 years’ experience. Outcomes were underlying principles of drug dosing, and error thresholds, as defined by proportion above and below reference range, for common PICU medications and clinical scenarios. Results Forty-four participants met eligibility, and response rates were 95, 86 and 84% for all three rounds respectively. Consensus was achieved for 13 of 15 principles, and 23 of 30 error thresholds. An over-dosed drug that is intercepted, an under-dose of a possibly life-saving medication, dosing 50% above or below target range and not adjusting for a drug interaction were agreed principles of dosing error. Altough there remained much uncertainty in defining dosing error, expert clinicians agreed that, for most medication categories and clinical scenarios, dosing over or below 10% of reference range was considered an error threshold. Conclusion Dosing principles and threshold are complex in pediatric critical care, and expert clinicians were uncertain about whether many scenarios were considered in error. For most intermittent medications, dosing over 10% below or above reference range was considered a dosing error, although this was largely influenced by clinical context and drug properties. This consensus driven error threshold will help guide routine clinical dosing practice, standardized reporting and drug quality improvement in pediatric critical care

    Clustering of Tir during enteropathogenic E. coli infection triggers calcium influx–dependent pyroptosis in intestinal epithelial cells

    No full text
    © 2020 Zhong et al.Clustering of the enteropathogenic Escherichia coli (EPEC) type III secretion system (T3SS) effector translocated intimin receptor (Tir) by intimin leads to actin polymerisation and pyroptotic cell death in macrophages. The effect of Tir clustering on the viability of EPEC-infected intestinal epithelial cells (IECs) is unknown. We show that EPEC induces pyroptosis in IECs in a Tir-dependent but actin polymerisation-independent manner, which was enhanced by priming with interferon gamma (IFNγ). Mechanistically, Tir clustering triggers rapid Ca2+ influx, which induces lipopolysaccharide (LPS) internalisation, followed by activation of caspase-4 and pyroptosis. Knockdown of caspase-4 or gasdermin D (GSDMD), translocation of NleF, which blocks caspase-4 or chelation of extracellular Ca2+, inhibited EPEC-induced cell death. IEC lines with low endogenous abundance of GSDMD were resistant to Tir-induced cell death. Conversely, ATP-induced extracellular Ca2+ influx enhanced cell death, which confirmed the key regulatory role of Ca2+ in EPEC-induced pyroptosis. We reveal a novel mechanism through which infection with an extracellular pathogen leads to pyroptosis in IECs.T.I.R and J.S.C are supported by the Cancer Research UK Centre grant C309/A25144. GF is supported a Wellcome Investigator Award 107057/Z/15/Z. QZ is supported by Imperial College President’s PhD Scholarship. GF is supported by a Wellcome Investigator Award (107057/Z/15/Z). T.I.R and J.S.C were funded by the CRUK Centre grant (C309/A25144)

    MSL's Widgets: Adding Rebustness to Martian Sample Acquisition, Handling, and Processing

    No full text
    Mars Science Laboratory's (MSL) Sample Acquisition Sample Processing and Handling (SA-SPaH) system is one of the most ambitious terrain interaction and manipulation systems ever built and successfully used outside of planet earth. Mars has a ruthless environment that has surprised many who have tried to explore there. The robustness widget program was implemented by the MSL project to help ensure the SA-SPaH system would be robust enough to the surprises of this ruthless Martian environment. The robustness widget program was an effort of extreme schedule pressure and responsibility, but was accomplished with resounding success. This paper will focus on a behind the scenes look at MSL's robustness widgets: the particle fun zone, the wind guards, and the portioner pokers
    corecore