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  • Spacecraft Propulsion and Power  (12)
  • Antarctica  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    The influence of microclimatic conditions on potential photosynthesis ofUsnea sphacelata: A model (1989)
    Springer
    Ecological research 4 (1989), S. 297-307 
    Details
    ISSN: 1440-1703
    Keywords: Antarctica ; Lichen activity ; Microclimate ; Modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract At a boulder on a hill near Casey Station, Wilkes Land, sensors for light, temperature and humidity were installed facing the four cardinal directions. The measurements lasted for about two months of the summer season 1985/86. The data recording was carried out at intervals of 6 minutes for all probes by automatic recording instruments. Data analysis was carried out with special regard to the biological effects of the parameters analyzed. These data of the microclimatic features taken from its original place of growth were used to a regression model of potential photosynthetic activity ofUsnea sphacelata, which is a characteristic species of this area. Although the individual time courses of the above mentioned parameters show long periods of favourable conditions for possible growth and metabolic processes, the combined analysis of these variables considering threshold values for metabolism shortens these time spans drastically. Thus, cross relationships within the physical descriptors and their effects on the actual values of photosynthesis as well as respiration become evident. They are illustrated by the results of models on photosynthesis and respiration ofU. sphacelata regarding the different cardinal directions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02348450
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    Paper (German National Licenses)
    Fulltext
  • 2
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    IHPRPT Steering Committee Meeting - NASA Spacecraft Propulsion Update (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-27
    Description: The activities and status of NASA Spacecraft Propulsion is presented including recent accomplishments.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN11245 , IHPRPT Steering Committee Meeting; 18 Sept. 2013; Edwards Air Force Base, California; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Forced Convection Boiling and Critical Heat Flux of Ethanol in Electrically Heated Tube Tests (1998)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Electrically heated tube tests were conducted to characterize the critical heat flux (transition from nucleate to film boiling) of subcritical ethanol flowing at conditions relevant to the design of a regeneratively cooled rocket engine thrust chamber. The coolant was SDA-3C alcohol (95% ethyl alcohol, 5% isopropyl alcohol by weight), and tests were conducted over the following ranges of conditions: pressure from 144 to 703 psia, flow velocities from 9.7 to 77 ft/s, coolant subcooling from 33 to 362 F, and critical heat fluxes up to 8.7 BTU/in(exp 2)/sec. For the data taken near 200 psia, critical heat flux was correlated as a function of the product of velocity and fluid subcooling to within +/- 20%. For data taken at higher pressures, an additional pressure term is needed to correlate the critical heat flux. It was also shown that at the higher test pressures and/or flow rates, exceeding the critical heat flux did not result in wall burnout. This result may significantly increase the engine heat flux design envelope for higher pressure conditions.
    Keywords: Spacecraft Propulsion and Power
    Type: NASA/TM-1998-206612 , E-11032 , NAS 1.15:206612 , AIAA Paper 98-1055 , Aerospace Sciences Meeting and Exhibit; Jan 12, 1998 - Jan 15, 1998; Reno, NV; United States
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    NASA TECHNICAL REPORTS
  • 4
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    Technology Area Roadmap for In-Space Propulsion Technologies (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The exponential increase of launch system size.and cost.with delta-V makes missions that require large total impulse cost prohibitive. Led by NASA fs Marshall Space Flight Center, a team from government, industry, and academia has developed a flight demonstration mission concept of an integrated electrodynamic (ED) tethered satellite system called PROPEL: \Propulsion using Electrodynamics.. The PROPEL Mission is focused on demonstrating a versatile configuration of an ED tether to overcome the limitations of the rocket equation, enable new classes of missions currently unaffordable or infeasible, and significantly advance the Technology Readiness Level (TRL) to an operational level. We are also focused on establishing a far deeper understanding of critical processes and technologies to be able to scale and improve tether systems in the future. Here, we provide an overview of the proposed PROPEL mission. One of the critical processes for efficient ED tether operation is the ability to inject current to and collect current from the ionosphere. Because the PROPEL mission is planned to have both boost and deboost capability using a single tether, the tether current must be capable of flowing in both directions and at levels well over 1 A. Given the greater mobility of electrons over that of ions, this generally requires that both ends of the ED tether system can both collect and emit electrons. For example, hollow cathode plasma contactors (HCPCs) generally are viewed as state-of-the-art and high TRL devices; however, for ED tether applications important questions remain of how efficiently they can operate as both electron collectors and emitters. Other technologies will be highlighted that are being investigated as possible alternatives to the HCPC such as Solex that generates a plasma cloud from a solid material (Teflon) and electron emission (only) technologies such as cold-cathode electron field emission or photo-electron beam generation (PEBG) techniques
    Keywords: Spacecraft Propulsion and Power
    Type: M12-1836 , M12-1798 , Global Space Exploration Conference; May 22, 2012 - May 24, 2012; Washinton, DC; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Roadmap for In-Space Propulsion Technology (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: NASA has created a roadmap for the development of advanced in-space propulsion technologies for the NASA Office of the Chief Technologist (OCT). This roadmap was drafted by a team of subject matter experts from within the Agency and then independently evaluated, integrated and prioritized by a National Research Council (NRC) panel. The roadmap describes a portfolio of in-space propulsion technologies that could meet future space science and exploration needs, and shows their traceability to potential future missions. Mission applications range from small satellites and robotic deep space exploration to space stations and human missions to Mars. Development of technologies within the area of in-space propulsion will result in technical solutions with improvements in thrust, specific impulse (Isp), power, specific mass (or specific power), volume, system mass, system complexity, operational complexity, commonality with other spacecraft systems, manufacturability, durability, and of course, cost. These types of improvements will yield decreased transit times, increased payload mass, safer spacecraft, and decreased costs. In some instances, development of technologies within this area will result in mission-enabling breakthroughs that will revolutionize space exploration. There is no single propulsion technology that will benefit all missions or mission types. The requirements for in-space propulsion vary widely according to their intended application. This paper provides an updated summary of the In-Space Propulsion Systems technology area roadmap incorporating the recommendations of the NRC.
    Keywords: Spacecraft Propulsion and Power
    Type: NASA/TM-2012-217641 , E-18195 , E-18195-1 , Space Propulsion 2012; May 07, 2012 - May 10, 2012; Bordeaux; France
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  • 6
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    Cryogenic Propellant Storage and Transfer (CPST) Tour Stop (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: No abstract available
    Keywords: Spacecraft Propulsion and Power
    Type: E-664451
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Technology Area Roadmap for In Space Propulsion Technologies (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This roadmap describes a portfolio of in-space propulsion technologies that can meet future space science and exploration needs.
    Keywords: Spacecraft Propulsion and Power
    Type: M11-0738 , 7th Symposium on Realistic Near-Term Advanced Scientific Space Missions; Jul 11, 2011 - Jul 14, 2011; Aosta; Italy
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    NASA TECHNICAL REPORTS
  • 8
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    Performance of the Spacecraft Propulsion Research Facility During Altitude Firing Tests of the Delta 3 Upper Stage (1998)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Spacecraft Propulsion Research Facility at the NASA Lewis Research Center's Plum Brook Station was reactivated in order to conduct flight simulation ground tests of the Delta 3 cryogenic upper stage. The tests were a cooperative effort between The Boeing Company, Pratt and Whitney, and NASA. They included demonstration of tanking and detanking of liquid hydrogen, liquid oxygen and helium pressurant gas as well as 12 engine firings simulating first, second, and third burns at altitude conditions. A key to the success of these tests was the performance of the primary facility systems and their interfaces with the vehicle. These systems included the structural support of the vehicle, propellant supplies, data acquisition, facility control systems, and the altitude exhaust system. While the facility connections to the vehicle umbilical panel simulated the performance of the launch pad systems, additional purge and electrical connections were also required which were unique to ground testing of the vehicle. The altitude exhaust system permitted an approximate simulation of the boost-phase pressure profile by rapidly pumping the test chamber from 13 psia to 0.5 psia as well as maintaining altitude conditions during extended steady-state firings. The performance of the steam driven ejector exhaust system has been correlated with variations in cooling water temperature during these tests. This correlation and comparisons to limited data available from Centaur tests conducted in the facility from 1969-1971 provided insight into optimizing the operation of the exhaust system for future tests. Overall, the facility proved to be robust and flexible for vehicle space simulation engine firings and enabled all test objectives to be successfully completed within the planned schedule.
    Keywords: Spacecraft Propulsion and Power
    Type: NASA/TM-1998-208477 , E-11247 , NAS 1.15:208477 , AIAA Paper 98-4010 , Propulsion; Jul 12, 1998 - Jul 15, 1998; Cleveland, OH; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 9
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    Cryogenic Fluid Management Technologies for Advanced Green Propulsion Systems (2007)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In support of the Exploration Vision for returning to the Moon and beyond, NASA and its partners are developing and testing critical cryogenic fluid propellant technologies that will meet the need for high performance propellants on long-term missions. Reliable knowledge of low-gravity cryogenic fluid management behavior is lacking and yet is critical in the areas of tank thermal and pressure control, fluid acquisition, mass gauging, and fluid transfer. Such knowledge can significantly reduce or even eliminate tank fluid boil-off losses for long term missions, reduce propellant launch mass and required on-orbit margins, and simplify vehicle operations. The Propulsion and Cryogenic Advanced Development (PCAD) Project is performing experimental and analytical evaluation of several areas within Cryogenic Fluid Management (CFM) to enable NASA's Exploration Vision. This paper discusses the status of the PCAD CFM technology focus areas relative to the anticipated CFM requirements to enable execution of the Vision for Space Exploration.
    Keywords: Spacecraft Propulsion and Power
    Type: NASA/TM-2007-214810 , AIAA Paper-2007-343 , 45th AIAA Aerospace Sciences Meeting and Exhibit; Jan 08, 2007 - Jan 11, 2007; Reno, NV; United States
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    NASA TECHNICAL REPORTS
  • 10
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    Technology Maturation in Preparation for the Cryogenic Propellant Storage and Transfer (CPST) Technology Demonstration Mission (TDM) (2014)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In support of its goal to find an innovative path for human space exploration, NASA embarked on the Cryogenic Propellant Storage and Transfer (CPST) Project, a Technology Demonstration Mission (TDM) to test and validate key cryogenic capabilities and technologies required for future exploration elements, opening up the architecture for large in-space cryogenic propulsion stages and propellant depots. Recognizing that key Cryogenic Fluid Management (CFM) technologies anticipated for on-orbit (flight) demonstration would benefit from additional maturation to a readiness level appropriate for infusion into the design of the flight demonstration, the NASA Headquarters Space Technology Mission Directorate (STMD) authorized funding for a one-year technology maturation phase of the CPST project. The strategy, proposed by the CPST Project Manager, focused on maturation through modeling, concept studies, and ground tests of the storage and fluid transfer of CFM technology sub-elements and components that were lower than a Technology Readiness Level (TRL) of 5. A technology maturation plan (TMP) was subsequently approved which described: the CFM technologies selected for maturation, the ground testing approach to be used, quantified success criteria of the technologies, hardware and data deliverables, and a deliverable to provide an assessment of the technology readiness after completion of the test, study or modeling activity. The specific technologies selected were grouped into five major categories: thick multilayer insulation, tank applied active thermal control, cryogenic fluid transfer, propellant gauging, and analytical tool development. Based on the success of the technology maturation efforts, the CPST project was approved to proceed to flight system development.
    Keywords: Spacecraft Propulsion and Power
    Type: GRC-E-DAA-TN14844 , E-18896 , Space Propulsion 2014; May 19, 2014 - May 22, 2014; Cologne; Germany
    Format: application/pdf
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