Applications of low lift to drag ratio aerobrakes using angle of attack variation for control

Several applications of low lift to drag ratio aerobrakes are investigated which use angle of attack variation for control. The applications are: return from geosynchronous or lunar orbit to low Earth orbit; and planetary aerocapture at Earth and Mars. A number of aerobrake design considerations are reviewed. It was found that the flow impingement behind the aerobrake and the aerodynamic heating loads are the primary factors that control the sizing of an aerobrake. The heating loads and other loads, such as maximum acceleration, are determined by the vehicle ballistic coefficient, the atmosphere entry conditions, and the trajectory design. Several formulations for defining an optimum trajectory are reviewed, and the various performance indices that can be used are evaluated. The 'nearly grazing' optimal trajectory was found to provide the best compromise between the often conflicting goals of minimizing the vehicle propulsive requirements and minimizing vehicle loads. The relationship between vehicle and trajectory design is investigated further using the results of numerical simulations of trajectories for each aerobrake application. The data show the sensitivity of the trajectories to several vehicle parameters and atmospheric density variations. The results of the trajectory analysis show that low lift to drag ratio aerobrakes, which use angle of attack variation for control, can potentially be used for a wide range of aerobrake applications

Paper Session III-B - Mars Transportation System Synthesis

President George Bush\u27s 1989 challenge to America to support the Space Exploration Initiative (SEI) of Back to the Moon and Manned Mission to Mars gives the space industry an opportunity to achieve effective and efficient space transportation systems (STS\u27s). This paper presents performance and requirements synthesized to support the manned Mars mission of the SEI. The information presented focuses primarily on the Mars transportation system (MTS), which uses nuclear thermal rocket (NTR) propulsion technology associated with accomplishing the manned Mars mission. Data are also shown for a propulsion system options comparison of chemical/ aerobrake and nuclear electric propulsion (NEP) systems

Cryogenic Propellant Storage and Transfer Technology Demonstration: Prephase A Government Point-of-Departure Concept Study

The primary purpose of this study was to define a point-of-departure prephase A mission concept for the cryogenic propellant storage and transfer technology demonstration mission to be conducted by the NASA Office of the Chief Technologist (OCT). The mission concept includes identification of the cryogenic propellant management technologies to be demonstrated, definition of a representative mission timeline, and definition of a viable flight system design concept. The resulting mission concept will serve as a point of departure for evaluating alternative mission concepts and synthesizing the results of industry- defined mission concepts developed under the OCT contracted studie

Lynx Mission Concept Status

Lynx is a concept under study for prioritization in the 2020 Astrophysics Decadal Survey. Providing orders of magnitude increase in sensitivity over Chandra, Lynx will examine the first black holes and their galaxies, map the large-scale structure and galactic halos, and shed new light on the environments of young stars and their planetary systems. In order to meet the Lynx science goals, the telescope consists of a high-angular resolution optical assembly complemented by an instrument suite that may include a High Definition X-ray Imager, X-ray Microcalorimeter and an X-ray Grating Spectrometer. The telescope is integrated onto the spacecraft to form a comprehensive observatory concept. Progress on the formulation of the Lynx telescope and observatory configuration is reported in this paper

Mild chronic kidney disease and functional impairment in community-dwelling older adults

Background: chronic kidney disease (CKD) has been associated with an increased risk of death and cardiovascular events, but its relationship with non-vascular outcomes, including functional impairment (FI), is less well understood. Objective: in this study, we review the association between CKD and FI, adjusting for potential confounders and risk factors, with a primary outcome of impairment in any instrumental ADL (IADL) or basic ADL (BADL). Design: the Cardiovascular Multimorbidity in Primary Care Study (CLARITY) is a cross-sectional study of community-dwelling adults. Setting: participants were adults living in the West of Ireland attending university-affiliated general practices. Subjects: all participants were adults aged >= 50 years living in the community. Methods: CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m(2). A standardised self-reported health questionnaire to measure activities of daily living (ADL) was completed by participants. Logistic regression analyses were used to determine the independent association between CKD and FI. Results: a total of 3,499 patients were included with a mean age of 66.2 +/- 10.3 years. 18.0% (n = 630) had CKD (mean eGFR 50.2 +/- 9.2 ml/min/1.73m(2)), 21.9% (n = 138) of which had a diagnosis of CKD documented in medical records. 40.4% (n = 1,413) reported FI and multivariable adjustment showed CKD to be independently associated with FI (OR: 1.43, 1.15-1.78), impairment in IADL (OR: 1.43, 1.15-1.78) and impairment in BADL (OR: 1.39, 1.11-1.75). Conclusion: our study shows even mild CKD is associated with FI, independent of age, gender, co-morbidities, traditional vascular risk factors and cardiovascular events

Evaluation of Amendments to Control Phosphorus Losses in Runoff from Dairy-Soiled Water

peer-reviewedAmendments with the potential to reduce phosphorus (P) losses from agricultural grassland arising from the land application of dairy-soiled water (DSW) were investigated. Optimal application rates were studied, and associated costs and feasibility were estimated. First, batch tests were carried out to identify appropriate chemicals or phosphorus sorbing materials to control P in runoff from DSW. Then, the best four treatments were examined in an agitator test. In this test, soil—placed in a beaker—was loaded with DSW or amended DSW at a rate equivalent to 5 mm ha−1 (the maximum permissible application rate of DSW allowable in a 42-day period in Ireland). The soil was overlain with continuously stirred water to simulate runoff on land-applied DSW. Optimum application rates were selected based on percentage removal of dissolved reactive phosphorus in overlying water and the estimated cost of amendment. The costs of the amendments, per cubic metre of DSW, increased in the order: bottom ash (1.55 €), alum (1.67 to 1.92 €), FeCl2·4H2O (3.55 to 8.15 €), and lime (20.31 to 88.65 €). The feasibility of the amendments, taking into account their cost, potential adverse effects, public perception, and their performance, decreased in the order: alum > FeCl2·4H2O > bottom ash > lime. Amendments to DSW could be introduced in critical source areas—areas where high soil test P and direct migration pathways to a receptor overlap.Department of Agriculture, Fisheries and Food (Ireland) Research Stimulus Programme 2007 (RSF 07 525