2,119 research outputs found

    Next Generation Life Support Project: Development of Advanced Technologies for Human Exploration Missions

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    Next Generation Life Support (NGLS) is one of several technology development projects sponsored by the National Aeronautics and Space Administration s Game Changing Development Program. NGLS is developing life support technologies (including water recovery, and space suit life support technologies) needed for humans to live and work productively in space. NGLS has three project tasks: Variable Oxygen Regulator (VOR), Rapid Cycle Amine (RCA) swing bed, and Alternative Water Processing. The selected technologies within each of these areas are focused on increasing affordability, reliability, and vehicle self sufficiency while decreasing mass and enabling long duration exploration. The RCA and VOR tasks are directed at key technology needs for the Portable Life Support System (PLSS) for an Exploration Extravehicular Mobility Unit (EMU), with focus on prototyping and integrated testing. The focus of the Rapid Cycle Amine (RCA) swing-bed ventilation task is to provide integrated carbon dioxide removal and humidity control that can be regenerated in real time during an EVA. The Variable Oxygen Regulator technology will significantly increase the number of pressure settings available to the space suit. Current spacesuit pressure regulators are limited to only two settings while the adjustability of the advanced regulator will be nearly continuous. The Alternative Water Processor efforts will result in the development of a system capable of recycling wastewater from sources expected in future exploration missions, including hygiene and laundry water, based on natural biological processes and membrane-based post treatment. The technologies will support a capability-driven architecture for extending human presence beyond low Earth orbit to potential destinations such as the Moon, near Earth asteroids and Mars

    The Effects of Atomic Oxygen on Patch Antenna Performance and Lifetime

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    The space environment is a volatile and challenging place for satellites to survive in. For Low Earth Orbiting (LEO) satellites, atomic oxygen (AO) is a constant corrosive effect that degrades the outer surface of satellites over long durations. Atomic oxygen exists in the atmosphere between 180 and 675 km and has a relatively high energy at 4.5 eV, which allows AO to break molecular bonds in materials on the surfaces of spacecraft. As the number and complexity of CubeSat missions increase, there is an increased risk that AO degradation on commercial off the shelf parts (COTS), such as antenna, could degrade the satellite’s ability to communicate with ground systems. This thesis looks at how AO erosion affects the performance of patch antennas for CubeSat applications. Patch antennas are small, cheap, low-profile antennas that can be used on CubeSats to communicate with the ground or other satellites. Patch antennas are semi-directional, providing higher gain and higher available frequencies than omnidirectional antennas. An AO chamber in the California Polytechnic State University San Luis Obispo’s (Cal Poly) Spacecraft Environments Testing Lab was used to expose the patch antennas for 24-hour and 48-hour tests. The 24-hour exposure saw an average AO fluence of 8.757 ± 0.807•1020 atoms/cm2 which corresponds to roughly 3.5 months of on-orbit AO exposure on the Ram side when in a 28.5° inclined orbit with an altitude of 400 km. The 48-hour exposure saw an average AO fluence of 1.595 ± 0.076•1021 atoms/cm2 which corresponds to approximately 6.4 months of on-orbit AO exposure on the Ram side when in a 28.5° inclined orbit with an altitude of 400 km. To test the performance of the patch antenna before and after AO exposure, an anechoic chamber in the Microwave Lab at Cal Poly was used to measure boresight gain and radiation pattern in the E-plane and H-plane. From the testing in the anechoic chamber it was determined that there was no apparent difference in the patch antenna’s gain and radiation pattern before and after AO exposure. By using a Fourier Transform Infrared Spectrometer (FTIR) it was discovered that the outer surface of the patch antennas were forming a silicon dioxide layer, which did not affect the performance of the patch antenna. Since silicon dioxide is resistant to AO erosion, it may be beneficial for CubeSats to include silica additives to their exposed antenna surfaces to prevent erosion

    Electron acceleration by cascading reconnection in the solar corona I Magnetic gradient and curvature effects

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    Aims: We investigate the electron acceleration in convective electric fields of cascading magnetic reconnection in a flaring solar corona and show the resulting hard X-ray (HXR) radiation spectra caused by Bremsstrahlung for the coronal source. Methods: We perform test particle calculation of electron motions in the framework of a guiding center approximation. The electromagnetic fields and their derivatives along electron trajectories are obtained by linearly interpolating the results of high-resolution adaptive mesh refinement (AMR) MHD simulations of cascading magnetic reconnection. Hard X-ray (HXR) spectra are calculated using an optically thin Bremsstrahlung model. Results: Magnetic gradients and curvatures in cascading reconnection current sheet accelerate electrons: trapped in magnetic islands, precipitating to the chromosphere and ejected into the interplanetary space. The final location of an electron is determined by its initial position, pitch angle and velocity. These initial conditions also influence electron acceleration efficiency. Most of electrons have enhanced perpendicular energy. Trapped electrons are considered to cause the observed bright spots along coronal mass ejection CME-trailing current sheets as well as the flare loop-top HXR emissions.Comment: submitted to A&

    The Lunar Mars Life Support Test Project

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    Advanced Life Support Technologies and Scenarios

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    As NASA looks beyond the International Space Station toward long-duration, deep space missions away from Earth, the current practice of supplying consumables and spares will not be practical nor affordable. New approaches are sought for life support and habitation systems that will reduce dependency on Earth and increase mission sustainability. To reduce launch mass, further closure of Environmental Control and Life Support Systems (ECLSS) beyond the current capability of the ISS will be required. Areas of particular interest include achieving higher degrees of recycling within Atmosphere Revitalization, Water Recovery and Waste Management Systems. NASA is currently investigating advanced carbon dioxide reduction processes that surpass the level of oxygen recovery available from the Sabatier Carbon Dioxide Reduction Assembly (CRA) on the ISS. Improving the efficiency of the recovery of water from spacecraft solid and liquid wastes is possible through use of emerging technologies such as the heat melt compactor and brine dewatering systems. Another significant consumable is that of food. Food production systems based on higher plants may not only contribute significantly to the diet, but also contribute to atmosphere revitalization, water purification and waste utilization. Bioreactors may be potentially utilized for wastewater and solid waste management. The level at which bioregenerative technologies are utilized will depend on their comparative requirements for spacecraft resources including mass, power, volume, heat rejection, crew time and reliability. Planetary protection requirements will need to be considered for missions to other solar system bodies

    Advanced Technologies to Improve Closure of Life Support Systems

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    As NASA looks beyond the International Space Station toward long-duration, deep space missions away from Earth, the current practice of supplying consumables and spares will not be practical nor affordable. New approaches are sought for life support and habitation systems that will reduce dependency on Earth and increase mission sustainability. To reduce launch mass, further closure of Environmental Control and Life Support Systems (ECLSS) beyond the current capability of the ISS will be required. Areas of particular interest include achieving higher degrees of recycling within Atmosphere Revitalization, Water Recovery and Waste Management Systems. NASA is currently investigating advanced carbon dioxide reduction processes that surpass the level of oxygen recovery available from the Sabatier Carbon Dioxide Reduction Assembly (CRA) on the ISS. Candidate technologies will potentially improve the recovery of oxygen from about 50% (for the CRA) to as much as 100% for technologies who's end product is solid carbon. Improving the efficiency of water recycling and recovery can be achieved by the addition of advanced technologies to recover water from brines and solid wastes. Bioregenerative technologies may be utilized for water reclaimation and also for the production of food. Use of higher plants will simultaneously benefit atmosphere revitalization and water recovery through photosynthesis and transpiration. The level at which bioregenerative technologies are utilized will depend on their comparative requirements for spacecraft resources including mass, power, volume, heat rejection, crew time and reliability. Planetary protection requirements will need to be considered for missions to other solar system bodies

    Standardized Entrance Assessment in Kindergarten: A Qualitative Analysis of the Experiences of Teachers, Administrators, and Parents

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    A brief narrative description of the journal article, document, or resource. This qualitative study examined experiences of teachers, parents, and administrators related to standardized kindergarten entrance assessment to identify strengths and weaknesses of standardized testing in kindergarten. Strengths emerging from the data included consistency of information with core curriculum, and the time and opportunity to begin parent-teacher dialogue. Weaknesses included the narrow scope of the information obtained. (Author/KB

    Use of Hydrogen Peroxide to Disinfect Hydroponic Plant Growth Systems

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    Hydrogen peroxide was studied as an alternative to conventional bleach and rinsing methods to disinfect hydroponic plant growth systems. A concentration of 0.5% hydrogen peroxide was found to be effective. Residual hydrogen peroxide can be removed from the system by repeated rinsing or by flowing the solution through a platinum on aluminum catalyst. Microbial populations were reduced to near zero immediately after treatment but returned to pre-disinfection levels 2 days after treatment. Treating nutrient solution with hydrogen peroxide and planting directly into trays being watered with the nutrient solution without replenishment, was found to be detrimental to lettuce germination and growth
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