330 research outputs found

    MCC level C formulation requirements. Shuttle TAEM targeting

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    The level C requirements for the shuttle orbiter terminal area energy management (TAEM) guidance and flight control functions to be incorporated into the Mission Control Center entry profile planning processor are described. This processor is used for preentry evaluation of the entry through landing maneuvers, and includes a simplified three degree-of-freedom model of the body rotational dynamics that is necessary to account for the effects of attitude response on the trajectory dynamics. This simulation terminates at TAEM-autoland interface

    STS-1 operational flight profile. Volume 5: Descent cycle 3. Appendix D: GRTLS six degree of freedom Monte Carlo dispersion analysis

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    The results of a six degree of freedom (6-DOF) nonlinear Monte Carlo dispersion analysis for the latest glide return to landing site (GRTLS) abort trajectory for the Space Transportation System 1 Flight are presented. For this GRTLS, the number two main engine fails at 262.5 seconds ground elapsed time. Fifty randomly selected simulations, initialized at external tank separation, are analyzed. The initial covariance matrix is a 20 x 20 matrix and includes navigation errors and dispersions in position and velocity, time, accelerometer bias, and inertial platform misalinements. In all 50 samples, speedbrake, rudder, elevon, and body flap hinge moments are acceptable. Transitions to autoland begin before 9,000 feet and there are no tailscrapes. Navigation derived dynamic pressure accuracies exceed the flight control system constraints above Mach 2.5. Three out of 50 landings exceeded tire specification limit speed of 222 knots. Pilot manual landings are expected to reduce landing speed by landing farther downrange

    A phase one AR/C system design

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    The Phase One AR&C System Design integrates an evolutionary design based on the legacy of previous mission successes, flight tested components from manned Rendezvous and Proximity Operations (RPO) space programs, and additional AR&C components validated using proven methods. The Phase One system has a modular, open architecture with the standardized interfaces proposed for Space Station Freedom system architecture

    Allowing Cities to Raise the Minimum Wage Could Prevent Hundreds of Infant Deaths Annually

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    This research brief discusses findings that show each additional dollar of minimum wage reduces infant deaths by up to 1.8% annually in large U.S. cities. Over 1,400 infants could be saved annually if localities were allowed to raise the minimum wage to $15. State laws that prevent cities and counties from raising their minimum wage contribute to infant deaths

    U.S. State Policy Contexts and Physical Health among Midlife Adults

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    This study examines how state policy contexts may have contributed to unfavorable adult health in recent decades. It merges individual-level data from the 1993–2016 Behavioral Risk Factor Surveillance System (n=2,166,835) with 15 state-level policy domains measured annually on a conservative to liberal continuum. We examined associations between policy domains and health among adults ages 45–64 years and assess how much of the associations is accounted by adults’ socioeconomic, behavioral/lifestyle, and family factors. A more liberal version of the civil rights domain was associated with better health. It was disproportionately important for less-educated adults and women, and its association with adult health was partly accounted by educational attainment, employment, and income. Environment, gun safety, and marijuana policy domains were, to a lesser degree, predictors of health in some model specifications. In sum, health improvements require a greater focus on macro-level factors that shape the conditions in which people live

    Alcohol's Collateral Damage: Childhood Exposure to Problem Drinkers and Subsequent Adult Mortality Risk

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    The importance of childhood circumstances, broadly defined, for shaping adult health and longevity is well-established. But the significance of one of the most prevalent childhood adversities—exposure to problem drinkers—has been understudied from a sociological perspective and remains poorly understood. We address this gap by drawing on cumulative inequality theory, using data from the 1988–2011 National Health Interview Survey-Linked Mortality Files, and estimating Cox proportional hazards models to examine the relationship between exposure to problem drinkers in childhood and adult mortality risk. Childhood exposure to problem drinkers is common (nearly 1 in 5 individuals were exposed) and elevates adult overall and cause-specific mortality risk. Compared to individuals who had not lived with a problem drinker during childhood, those who had done so suffered 17 percent higher risk of death (p<.001) over the follow-up period, net of age, sex, and race/ethnicity. We find compelling evidence that the duration, source, and intensity of exposure to problem drinkers in childhood contributes to inequality in adult mortality risk. Favorable socioeconomic status in adulthood does not ameliorate the consequences of childhood exposure to problem drinkers. The primary intervening mechanisms are risky behaviors, including adult drinking and smoking. The findings—which reveal that the influence of problem drinking is far-reaching and long-term—should inform policies to improve childhood circumstances, reduce detrimental effects of problem drinking, and increase life expectancy
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