268 research outputs found

    Production and use of metals and oxygen for lunar propulsion

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    Production, power, and propulsion technologies for using oxygen and metals derived from lunar resources are discussed. The production process is described, and several of the more developed processes are discussed. Power requirements for chemical, thermal, and electrical production methods are compared. The discussion includes potential impact of ongoing power technology programs on lunar production requirements. The performance potential of several possible metal fuels including aluminum, silicon, iron, and titanium are compared. Space propulsion technology in the area of metal/oxygen rocket engines is discussed

    Extraction of Water from Martian Regolith Simulant via Open Reactor Concept

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    To demonstrate proof of concept water extraction from simulated Martian regolith, an open reactor design is presented along with experimental results. The open reactor concept avoids sealing surfaces and complex moving parts. In an abrasive environment like the Martian surface, those reactor elements would be difficult to maintain and present a high probability of failure. A general lunar geotechnical simulant was modified by adding borax decahydrate (Na2B4O710H2O) (BDH) to mimic the ~ 3 percent water content of hydrated salts in near surface soils on Mars. A rotating bucket wheel excavated the regolith from a source bin and deposited the material onto an inclined copper tray, which was fitted with heaters and a simple vibration system. The combination of vibration, tilt angle and heat was used to separate and expose as much regolith surface area as possible to liberate the water contained in the hydrated minerals, thereby increasing the efficiency of the system. The experiment was conducted in a vacuum system capable of maintaining a Martian like atmosphere. Evolved water vapor was directed to a condensing system using the ambient atmosphere as a sweep gas. The water vapor was condensed and measured. Processed simulant was captured in a collection bin and weighed in real time. The efficiency of the system was determined by comparing pre- and post-processing soil mass along with the volume of water captured

    System Modeling of Lunar Oxygen Production: Mass and Power Requirements

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    A systems analysis tool for estimating the mass and power requirements for a lunar oxygen production facility is introduced. The individual modeling components involve the chemical processing and cryogenic storage subsystems needed to process a beneficiated regolith stream into liquid oxygen via ilmenite reduction. The power can be supplied from one of six different fission reactor-converter systems. A baseline system analysis, capable of producing 15 metric tons of oxygen per annum, is presented. The influence of reactor-converter choice was seen to have a small but measurable impact on the system configuration and performance. Finally, the mission concept of operations can have a substantial impact upon individual component size and power requirements

    Coronavirus replication-transcription complex:Vital and selective NMPylation of a conserved site in nsp9 by the NiRAN-RdRp subunit

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    RNA-dependent RNA polymerases (RdRps) of the Nidovirales (Coronaviridae, Arteriviridae, and 12 other families) are linked to an amino-terminal (N-terminal) domain, called NiRAN, in a non-structural protein (nsp) that is released from polyprotein 1ab by the viral main protease (Mpro). Previously, self-GMPylation/UMPylation activities were reported for an arterivirus NiRAN-RdRp nsp and suggested to generate a transient state primed for transferring nucleoside monophosphate (NMP) to (currently unknown) viral and/or cellular biopolymers. Here, we show that the coronavirus (human coronavirus [HCoV]-229E and severe acute respiratory syndrome coronavirus 2) nsp12 (NiRAN-RdRp) has Mn2+-dependent NMPylation activity that catalyzes the transfer of a single NMP to the cognate nsp9 by forming a phosphoramidate bond with the primary amine at the nsp9 N terminus (N3825) following M-pro-mediated proteolytic release of nsp9 from N-terminally flanking nsps. Uridine triphosphate was the preferred nucleotide in this reaction, but also adenosine triphosphate, guanosine triphosphate, and cytidine triphosphate were suitable cosubstrates. Mutational studies using recombinant coronavirus nsp9 and nsp12 proteins and genetically engineered HCoV-229E mutants identified residues essential for NiRAN-mediated nsp9 NMPylation and virus replication in cell culture. The data corroborate predictions on NiRAN active-site residues and establish an essential role for the nsp9 N3826 residue in both nsp9 NMPylation in vitro and virus replication. This residue is part of a conserved N-terminal NNE tripeptide sequence and shown to be the only invariant residue in nsp9 and its homologs in viruses of the family Coronaviridae. The study provides a solid basis for functional studies of other nidovirus NMPylation activities and suggests a possible target for antiviral drug development.Molecular basis of virus replication, viral pathogenesis and antiviral strategie

    Orientational order parameters of a de Vries–type ferroelectric liquid crystal obtained by polarized Raman spectroscopy and x-ray diffraction

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    The orientational order parameters 〈P2〉 and 〈P4〉 of the ferroelectric, de Vries–type liquid crystal 9HL have been determined in the SmA* and SmC* phases by means of polarized Raman spectroscopy, and in the SmA* phase using x-ray diffraction. Quantum density functional theory predicts Raman spectra for 9HL that are in good agreement with the observations and indicates that the strong Raman band probed in the experiment corresponds to the uniaxial, coupled vibration of the three phenyl rings along the molecular long axis. The magnitudes of the orientational order parameters obtained in the Raman and x-ray experiments differ dramatically from each other, a discrepancy that is resolved by considering that the two techniques probe the orientational distributions of different molecular axes. We have developed a systematic procedure in which we calculate the angle between these axes and rescale the orientational order parameters obtained from x-ray scattering with results that are then in good agreement with the Raman data. At least in the case of 9HL, the results obtained by both techniques support a “sugar loaf” orientational distribution in the SmA* phase with no qualitative difference to conventional smectics A. The role of individual molecular fragments in promoting de Vries–type behavior is considered

    ISRU at a Lunar Outpost: Implementation and Opportunities for Partnerships and Commercial Development

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    The NASA Lunar Architecture Team (LAT), which was commissioned to help answer the question "how" will humans return to the Moon, and the Synthesis Team and the recently released Global Exploration Strategy, which was commissioned to help answer the question "why" will humans return to the Moon and go on to Mars have identified the ability to extract and use in-situ resources as important to extending human frontiers, reduce dependence on Earth, and further economic and commercial expansion into space. The extraction and processing of space resources into useful products, known as In-Situ Resource Utilization (ISRU), can have a substantial impact on mission and architecture concepts. In particular, the ability to make propellants, life support consumables, and fuel cell reagents can significantly reduce the cost, mass, and risk of sustained human activities beyond Earth. Potential lunar resources include solar wind implanted volatiles, vast quantities of metal and mineral oxides, possible water/ice at the poles, abundant solar energy, regions of permanent light and darkness, the vacuum of space itself, and even scavenging leftover descent propellants and/or trash and waste from human crew activities. Suitable processing can transform these raw resources into useful materials and products. The establishment of a human lunar Outpost, as proposed by NASA at the 2nd Space Exploration Conference in Houston in December 2006, opens up the possibility for the first time of breaking our reliance on Earth supplied consumables and learn to "live off the land". The ISRU phasing and capability incorporation strategy developed during LAT Phase I & II is based on the premise that while ISRU is a critical capability and key to successful implementation of the US Vision for Space Exploration, it is also an unproven capability for human lunar exploration and can not be put in the critical path of architecture success until it has been proven. Therefore, ISRU needs to take incremental steps toward the desired end state. However, at the same time, the lunar architecture needs to be open enough to take advantage of ISRU when proven available

    NASA Oxygen and Water Production Architectures for Early Reusable Lander

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    The presentation covers two recent studies Lunar In Situ Resource Utilization (ISRU) systems to produce propellant for an early reusable lander architecture. The first study examines the hardware, power, and operations required to produce 10 metric tons of oxygen per year near the lunar south pole using the Carbothermal Reduction process. The second study examines the hardware, power, and operations to mine and process 15 metric tons of water from a permanently shadowed crater near Shackleton crater

    Results from the NASA Capability Roadmap Team for In-Situ Resource Utilization (ISRU)

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    On January 14, 2004, the President of the United States unveiled a new vision for robotic and human exploration of space entitled, "A Renewed Spirit of Discovery". As stated by the President in the Vision for Space Exploration (VSE), NASA must "... implement a sustained and affordable human and robotic program to explore the solar system and beyond " and ".. .develop new technologies and harness the moon's abundant resources to allow manned exploration of more challenging environments." A key to fulfilling the goal of sustained and affordable human and robotic exploration will be the ability to use resources that are available at the site of exploration to "live off the land" instead of bringing everything from Earth, known as In-Situ Resource Utilization (ISRU). ISRU can significantly reduce the mass, cost, and risk of exploration through capabilities such as: mission consumable production (propellants, fuel cell reagents, life support consumables, and feedstock for manufacturing & construction); surface construction (radiation shields, landing pads, walls, habitats, etc.); manufacturing and repair with in-situ resources (spare parts, wires, trusses, integrated systems etc.); and space utilities and power from space resources. On January 27th, 2004 the President's Commission on Implementation of U.S. Space Exploration Policy (Aldridge Committee) was created and its final report was released in June 2004. One of the report's recommendations was to establish special project teams to evaluate enabling technologies, of which "Planetary in situ resource utilization" was one of them. Based on the VSE and the commission's final report, NASA established fifteen Capability Roadmap teams, of which ISRU was one of the teams established. From Oct. 2004 to May 2005 the ISRU Capability Roadmap team examined the capabilities, benefits, architecture and mission implementation strategy, critical decisions, current state-of-the-art (SOA), challenges, technology gaps, and risks of ISRU for future human Moon and Mars exploration. This presentation will provide an overview of the ISRU capability, architecture, and implementation strategy examined by the ISRU Capability Roadmap team, along with a top-level review of ISRU benefits, resources and products of interest, and the current SOA in ISRU processes and systems. The presentation will also highlight the challenges of incorporating ISRU into future missions and the gaps in technologies and capabilities that need to be filled to enable ISRU
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