314 research outputs found

    Development Status of the J-2X

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    In June 2006, the NASA Marshall Space Flight Center (MSFC) and Pratt & Whitney Rocketdyne began development of an engine for use on the Ares I crew launch vehicle and the Ares V cargo launch vehicle. The development program will be completed in December 2012 at the end of a Design Certification Review and after certification testing of two flight configuration engines. A team of over 600 people within NASA and Pratt & Whitney Rocketdyne are currently working to prepare for the fall 2008 Critical Design Review (CDR), along with supporting an extensive risk mitigation test program. The J-2X will power the Ares I upper stage and the Ares V earth departure stage (EDS). The initial use will be in the Ares I, used to launch the Orion crew exploration vehicle. In this application, it will power the upper stage after being sent aloft on a Space Shuttle-derived. 5-segment solid rocket booster first stage. In this mission. the engine will ignite at altitude and provide the necessary acceleration force to allow the Orion to achieve orbital velocity. The Ares I upper stage, along with the J-2X. will then be expended. On the Ares V. first stage propulsion is provided by five RS-68B engines and two 5-segment boosters similar to the Ares I configuration. In the Ares V mission. the J-2X is first started to power the EDS and its payload. the Altair lunar lander. into earth orbit, then shut-down and get prepared for its next start. The EDS/Altair will remain in a parking orbit, awaiting rendezvous and docking with Orion. Once the two spacecraft are mated, the J-2X will be restarted to achieve earth departure velocity. After powering the Orion and Altair, the EDS will be expended. By using the J-2X Engine in both applications, a significant infrastructure cost savings is realized. Only one engine development is required, and the sustaining engineering and flight support infrastructures can be combined. There is also flexibility for changing, the production and flight manifest because a single production line can support both missions with minimal differences between each engine configuration kit

    Launching to the Moon, Mars, and Beyond

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    This presentation presents the goals of the Vision for Space Exploration. It gives a general overview of the Ares I and Ares V launch vehicles and shows how they enable NASA's lunar exploration missions. It explains how space exploration can inspire the next generation of explorers

    RS-25 for the NASA Cargo Launch Vehicle: The Evolution of SSME for Space Exploration

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    A key element of the National Vision for Space Exploration is the development of a heavy-lift Cargo Launch Vehicle (CaLV). Missions to the Moon, Mars, and beyond are only possible with the logistical capacity of putting large payloads in low-earth orbit. However, beyond simple logistics, there exists the need for this capability to be as cost effective as possible to ensure mission sustainability. An element of the CaLV project is, therefore, the development of the RS-25, which represents the evolution of the proven Space Shuttle Main Engine (SSME) into a high-performance, cost-effective expendable rocket engine. The development of the RS-25 will be built upon the foundation of over one million seconds of accumulated hot-fire time on the SSME. Yet in order to transform the reusable SSME into the more cost-effective, expendable RS-25 changes will have to be made. Thus the project will inevitably strive to maintain a balance between demonstrated heritage products and processes and the utilization of newer technology developments. Towards that end, the Core Stage Engine Office has been established at the NASA Marshall Space Flight Center to initiate the design and development of the RS-25 engine. This paper is being written very early in the formulation phase of the RS-25 project. Therefore the focus of this paper will be to present the scope, challenges, and opportunities for the RS-25 project. Early schedules and development decisions and plans will be explained. For not only must the RS-25 project achieve cost effectiveness through the development of new, evolved components such as a channel-wall nozzle, a new HIP-bonded main combustion chamber, and several others, it must simultaneously develop the means whereby this engine can be manufactured on a scale never envisioned for the SSME. Thus, while the overall project will span the next eight to ten years, there is little doubt that even this schedule is aggressive with a great deal of work to accomplish

    Progress on the J-2X Upper Stage Engine for the Ares I Crew Launch Vehicle and the Ares V Cargo Launch Vehicle

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    NASA's Vision for Exploration requires a safe, reliable, affordable upper stage engine to power the Ares I Crew Launch Vehicle (CLV) and the Ares V Cargo Launch Vehicle. The J-2X engine is being developed for that purpose, epitomizing NASA's philosophy of employing legacy knowledge, heritage hardware, and commonality to carry the next generation of explorers into low-Earth orbit and out into the solar system This presentation gives top-level details on accomplishments to date and discusses forward work necessary to bring the J-2X engine to the launch pad

    Application of the Transtheoretical Model in Hispanic and African American Populations to Assess Deceased Kidney Donor Noncompliance

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    Given existing health disparities such as financial barriers, lack of education and inadequate health care in minority communities, the rates of deceased kidney donation continues to decline. The transtheoretical model (TTM) assesses the patients’ willingness to pursue deceased kidney donation through application of a stage structured curriculum. Patients are evaluated into five different stage groups; pre-contemplation, contemplation, preparation, action, and maintenance. This assessment of behavior change as applied to the willingness of a patient to pursue a deceased kidney donor transplant can be tracked over time and used to help determine what stage of change a patient is in during their kidney transplant evaluation process. Self-reported reasons why members from these communities opt out of deceased donation or who don’t complete their transplant evaluation process will be examined as well as possible solutions to alleviate some of the barriers that preclude these patients from completing evaluation will be proposed. Research is continuing and results are not final

    Living Donor Kidney Transplantation: A Focus on the Socioecological Model to Determine Why Hispanics/Latinos Have a Disproportionate Amount of Kidney Transplants When Compared to Other Ethnic Groups

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    Health disparities, especially kidney transplantation disparities, are prevalent in the Hispanic/Latino community. In order to decrease existing kidney transplantation disparities in the Hispanic/Latino community, culturally tailored education surrounding living donor kidney transplants needs to be improved. The socioecological model depicts factors that affect a patient’s decision making when deciding on obtaining a living kidney donor transplant. These factors often act as barriers, which are categorized as patient-level factors, provider factors, and system factors. Patient-level factors include family and social networks, provider factors include physician and/or health care provider relationships, and system level factors include health care organization efficiency. Developing patient education tools (i.e. videos, pamphlets, brochures, factsheets) that address these potential barriers would alleviate some of the patient concerns and perceived hindrances to kidney transplantation. The methodology requires patient interaction in the form of interviews and data retrieval from online sysmtems. Although the results of this study are not concluded it is expected that Hispanics/Latinos have a disproportionate amount of kidney transplants when compared to other ethnic groups due to factors such as familism and lack of living donor kidney transplantation knowledge

    NASA Propulsion Investments for Exploration and Science

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    The National Aeronautics and Space Administration (NASA) invests in chemical and electric propulsion systems to achieve future mission objectives for both human exploration and robotic science. Propulsion system requirements for human missions are derived from the exploration architecture being implemented in the Constellation Program. The Constellation Program first develops a system consisting of the Ares I launch vehicle and Orion spacecraft to access the Space Station, then builds on this initial system with the heavy-lift Ares V launch vehicle, Earth departure stage, and lunar module to enable missions to the lunar surface. A variety of chemical engines for all mission phases including primary propulsion, reaction control, abort, lunar ascent, and lunar descent are under development or are in early risk reduction to meet the specific requirements of the Ares I and V launch vehicles, Orion crew and service modules, and Altair lunar module. Exploration propulsion systems draw from Apollo, space shuttle, and commercial heritage and are applied across the Constellation architecture vehicles. Selection of these launch systems and engines is driven by numerous factors including development cost, existing infrastructure, operations cost, and reliability. Incorporation of green systems for sustained operations and extensibility into future systems is an additional consideration for system design. Science missions will directly benefit from the development of Constellation launch systems, and are making advancements in electric and chemical propulsion systems for challenging deep space, rendezvous, and sample return missions. Both Hall effect and ion electric propulsion systems are in development or qualification to address the range of NASA s Heliophysics, Planetary Science, and Astrophysics mission requirements. These address the spectrum of potential requirements from cost-capped missions to enabling challenging high delta-v, long-life missions. Additionally, a high specific impulse chemical engine is in development that will add additional capability to performance-demanding space science missions. In summary, the paper provides a survey of current NASA development and risk reduction propulsion investments for exploration and science
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