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845 Matching Results
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WET MARS: plentiful, readily-available martian water and its implications
Water and its major constituent, oxygen, in large specific quantities are essential for maintenance of human life. Providing them in adequate quantities is widely believed to be a major challenge for human Mars exploration and settlement. The Martian regolith isn't known to bear either water or hydrogen, the ice-rich Martian polar regions are thermally inhospitable, and the measured water content of Mars' thin atmosphere represents a layer of liquid water of average thickness only about 1% that of the Moon: {approximately}0.001 cm. Crucially, however, the atmospheric Martian water inventory is advected to everyplace on Mars by meteorological phenomena, so that the few cubic kilometers of liquid water-equivalent in the atmosphere are available most anywhere when, merely for the effort of condensing it. Well-engineered apparatus deployed essentially anywhere on Mars can condense water from the atmosphere in daily quantities not much smaller than its own mass, rejecting into space from radiators deployed over the local terrain the water's heat-of-condensation and the heat from non-ideality of the equipment's operation. Thus, an optimized, photovoltaically-powered 0.3 ton water-condensing system could strip 40 tons of water each year from {approximately}10{sup 4} times this mass of thin, dry Martian air. Given a 480 set I{sub sp} …
Date:
August 12, 1999
Creator:
Hyde, R.; Ishikawa, M.; Nuckolls, J.; Whitehead, J. & Wood, L.
Object Type:
Article
System:
The UNT Digital Library
Propulsion engineering study for small-scale Mars missions
Rocket propulsion options for small-scale Mars missions are presented and compared, particularly for the terminal landing maneuver and for sample return. Mars landing has a low propulsive {Delta}v requirement on a {approximately}1-minute time scale, but at a high acceleration. High thrust/weight liquid rocket technologies, or advanced pulse-capable solids, developed during the past decade for missile defense, are therefore more appropriate for small Mars landers than are conventional space propulsion technologies. The advanced liquid systems are characterize by compact lightweight thrusters having high chamber pressures and short lifetimes. Blowdown or regulated pressure-fed operation can satisfy the Mars landing requirement, but hardware mass can be reduced by using pumps. Aggressive terminal landing propulsion designs can enable post-landing hop maneuvers for some surface mobility. The Mars sample return mission requires a small high performance launcher having either solid motors or miniature pump-fed engines. Terminal propulsion for 100 kg Mars landers is within the realm of flight-proven thruster designs, but custom tankage is desirable. Landers on a 10 kg scale also are feasible, using technology that has been demonstrated but not previously flown in space. The number of sources and the selection of components are extremely limited on this smallest scale, so some customized …
Date:
September 12, 1995
Creator:
Whitehead, J.
Object Type:
Report
System:
The UNT Digital Library
Mars ascent propulsion options for small sample return vehicles
None
Date:
May 12, 1997
Creator:
Whitehead, J. C., LLNL
Object Type:
Article
System:
The UNT Digital Library
Modeling radiation loads to detectors in a SNAP mission
In order to investigate degradation of optical detectors of the Supernova Acceleration Project (SNAP) space mission due to irradiation, a three-dimensional model of the satellite has been developed. Realistic radiation environment at the satellite orbit, including both galactic and trapped in radiation belts cosmic rays, has been taken into account. The modeling has been performed with the MARS14 Monte Carlo code. In a current design, the main contribution to dose accumulated in the photodetectors is shown to be due to trapped protons. A contribution of primary {alpha}-particles is estimated. Predicted performance degradation for the photo-detector for a 4-year space mission is 40% and can be reduced further by means of shielding optimization.
Date:
May 12, 2004
Creator:
al., Nikolai V. Mokhov et
Object Type:
Article
System:
The UNT Digital Library
The National Aeronautics and Space Administration's FY2000 Budget and FY2000-FY2002 Authorization: Description and Analysis
None
Date:
September 12, 2000
Creator:
Rowberg, Richard E.
Object Type:
Report
System:
The UNT Digital Library
The Sachse News (Sachse, Tex.), Vol. 4, No. 20, Ed. 1 Thursday, June 12, 2008
Weekly newspaper from Sachse, Texas that includes local, state and national news along with advertising.
Date:
June 12, 2008
Creator:
Fisher, Donnita Nesbit
Object Type:
Newspaper
System:
The Portal to Texas History
Federal Research and Development Funding: FY2014
This report provides government-wide, multi-agency, and individual agency analyses of the President's FY2014 request as it relates to R&D and related activities. The President's budget seeks $142.773 billion for R&D in FY2014, a 1.3% increase (0.7% CAGR) over the actual FY2012 R&D funding level of $140.912 billion. Adjusted for inflation, the President's FY2014 R&D request represents a decrease of 2.6% from the FY2012 level (1.3% CAGR).
Date:
September 12, 2013
Creator:
Sargent, John F., Jr.
Object Type:
Report
System:
The UNT Digital Library
De Leon Free Press (De Leon, Tex.), Vol. 116, No. 15, Ed. 1 Thursday, October 12, 2006
Weekly newspaper from De Leon, Texas that includes local, state, and national news along with advertising.
Date:
October 12, 2006
Creator:
Kestner, Laura
Object Type:
Newspaper
System:
The Portal to Texas History
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 82, No. 310, Ed. 1 Friday, September 12, 1997
Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date:
September 12, 1997
Creator:
Diehl, Don
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
United States and Soviet Progress in Space: Some New Contrasts
This report discusses the history of the "Space Race" between the United States and the Soviet Union and compares each nations accomplishments and current projects as well as future prospects.
Date:
January 12, 1971
Creator:
Sheldon, Charles S. III
Object Type:
Report
System:
The UNT Digital Library
Oklahoma City Times (Oklahoma City, Okla.), Vol. 79, No. 19, Ed. 3 Tuesday, March 12, 1968
Daily newspaper from Oklahoma City, Oklahoma that includes local, state, and national news along with advertising.
Date:
March 12, 1968
Creator:
Gaylord, E. K.
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
NASA: Major Management Challenges and Program Risks
Testimony issued by the General Accounting Office with an abstract that begins "Since its inception, the National Aeronautics and Space Administration (NASA) has undertaken numerous programs that have greatly advanced scientific and technological knowledge. NASA's activities span a broad range of complex and technical endeavors. But the agency is at a critical juncture, and major management improvements are needed. In January of this year, we identified four challenges facing NASA: (1) strengthening strategic human capital management, (2) improving contract management; (3) controlling International Space Station costs, and (4) reducing space launch costs."
Date:
June 12, 2003
Creator:
United States. General Accounting Office.
Object Type:
Text
System:
The UNT Digital Library
NASA Needs to Better Assess Contract Termination Liability Risks and Ensure Consistency in Its Practices
Correspondence issued by the Government Accountability Office with an abstract that begins "The National Aeronautics and Space Administration (NASA) procures most of its goods and services through contracts, and it terminates very few of them. In fiscal year 2010, for example, NASA's procurements, ranging from small contracts for human resources consulting services to multimillion dollar contracts to build and operate spacecraft, totaled approximately $17.4 billion, representing about 83.4 percent of the agency's obligations that year. That same year, it terminated 28 of 16,343 active contracts and orders--a termination rate of about .17 percent. This rate is about the same--less than 0.2 percent--for each of the past 5 fiscal years. NASA contract terminations--the complete or partial cancellation of work under a contract before the contract's period of performance ends--are rare but could become more common in the future. The federal government is facing real fiscal limitations and will have to make difficult choices about upcoming priorities. This reality makes it more important than ever that NASA manage its projects as efficiently and effectively as possible and within its budget. This is a struggle for NASA. Our work has shown that NASA's large-scale projects tend to cost more and take longer to …
Date:
July 12, 2011
Creator:
United States. Government Accountability Office.
Object Type:
Text
System:
The UNT Digital Library
TOUGH+/GasH20 study of the effects of a heat source buried in theMartian permafrost
We use TOUGH+/GasH2O to study the effects of a heat sourceburied in the Martian permafrost to evaluate the possibility ofestablishing a wet zone of liquid water, in which terrestrialmicroorganisms could survive and multiply. Analysis of the problemindicates that (1) only a limited permafrost volume (not exceeding 0.35 min radius) is affected, (2) a "wet" zone with limited amounts of liquidwater de-velops (not exceeding 8 and 0.7 kg for a 250 W and a 62.5 Wsource, respectively), (3) the wet zone per-sists for a long time,becomes practically stationary after t = 20 sols because of venting intothe Martian atmosphere, and its thickness is limited and decreases slowlyover time, (4) a "dry" zone (where SG>0.9) evolves, continues toexpand (albeit slowly) with time, but its extent remains limited, and (5)the ice front surrounding the wet zone is self-sharpening. For a range ofinitial conditions investigated, evolution of the liquid water massoccurs at approximately the same rate, reaches roughly the same maximum,and occurs at about the same time (10 to 20 sols; 1 sol = 24.39hours).
Date:
May 12, 2006
Creator:
Moridis, George J. & Pruess, Karsten
Object Type:
Article
System:
The UNT Digital Library
Federal Research and Development Funding: FY2007
None
Date:
July 12, 2006
Creator:
Davey, Michael E.; Matthews, Christine M.; Moteff, John D.; Morgan, Daniel; Schacht, Wendy H.; Smith, Pamela W. et al.
Object Type:
Report
System:
The UNT Digital Library
SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS
We are now entering the final stages of our ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342). We have now developed several techniques to help distinguish economic hydrocarbon deposits from false ''Fizz'' gas signatures. These methods include using the proper in situ rock and fluid properties, evaluating interference effects on data, and doing better constrained inversions for saturations. We are testing these techniques now on seismic data from several locations in the Gulf of Mexico. In addition, we are examining the use of seismic attenuation as indicated by frequency shifts below potential reservoirs. During this quarter we have: Began our evaluation of our latest data set over the Neptune Field; Developed software for computing composite reflection coefficients; Designed and implemented stochastic turbidite reservoir models; Produced software & work flow to improve frequency-dependent AVO analysis; Developed improved AVO analysis for data with low signal-to-noise ratio; and Examined feasibility of detecting fizz gas using frequency attenuation. Our focus on technology transfer continues, both by generating numerous presentations for the upcoming SEG annual meeting, and by beginning our planning for our next DHI minisymposium next spring.
Date:
August 12, 2005
Creator:
Batzle, Michael; Han, D-h; Gibson, R. & James, Huw
Object Type:
Report
System:
The UNT Digital Library
Port Aransas South Jetty (Port Aransas, Tex.), Vol. 9, No. 4, Ed. 1 Thursday, July 12, 1979
Weekly newspaper from Port Aransas, Texas on Mustang Island that includes local, state and national news along with extensive advertising.
Date:
July 12, 1979
Creator:
Frishman, Steve
Object Type:
Newspaper
System:
The Portal to Texas History
Comet 81P/Wild 2 under a microscope
The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales. Stardust was the first mission to return solid samples from a specific astronomical body other than the Moon. The mission, part of the NASA Discovery program, retrieved samples from a comet that is believed to have formed at the outer fringe of the solar nebula, just beyond the most distant planet. The samples, isolated from the planetary region of the solar system for billions of years, provide new insight into the formation of the solar system. The samples provide unprecedented opportunities both to corroborate astronomical (remote sensing) and sample analysis information (ground truth) on a known …
Date:
October 12, 2006
Creator:
Brownlee, D; Tsou, P.; Aleon, J.; Alexander, C.; Araki, T.; Bajt, S. et al.
Object Type:
Article
System:
The UNT Digital Library
The Llano News (Llano, Tex.), Vol. 100, No. 38, Ed. 1 Thursday, July 12, 1990
Weekly newspaper from Llano, Texas that includes local, state, and national news along with advertising.
Date:
July 12, 1990
Creator:
Buckner, Walter L.
Object Type:
Newspaper
System:
The Portal to Texas History
Federal Advertising: Established Programs Were Largely Used to Address Executive Order Directive to Ensure Small and Minority-Owned Business Participation
A letter report issued by the Government Accountability Office with an abstract that begins "In 2005, federal spending on advertising exceeded $1 billion. Five agencies--DOD, Treasury, HHS, Interior, and NASA--together made up over 90 percent of this spending from 2001 to 2005. Executive Order 13170, signed in October 2000, directs agencies to take an aggressive role in ensuring substantial participation in federal advertising contracts by businesses in the Small Business Administration's (SBA) 8(a) and small disadvantaged business (SDB) programs and minority-owned businesses. This report describes (1) strategies DOD, HHS, Treasury, Interior, and NASA used to address Executive Order 13170, and (2) the total obligations, number of contract actions, and percentage of total obligations represented by these actions that each agency awarded to 8(a)s, SDBs, and minority-owned businesses for advertising services. In conducting this study, GAO analyzed agency contracting data and executive order implementation plans and interviewed agency procurement officials."
Date:
July 12, 2007
Creator:
United States. Government Accountability Office.
Object Type:
Report
System:
The UNT Digital Library
The Kermit Daily Sun (Kermit, Tex.), Vol. 2, No. 92, Ed. 1 Friday, March 12, 1965
Daily newspaper from Kermit, Texas that includes local, state, and national news along with advertising.
Date:
March 12, 1965
Creator:
Sclair, Dave
Object Type:
Newspaper
System:
The Portal to Texas History
The Altus Times-Democrat (Altus, Okla.), Vol. 39, No. 111, Ed. 1 Friday, February 12, 1965
Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date:
February 12, 1965
Creator:
Buckley, Callaway
Object Type:
Newspaper
System:
The Gateway to Oklahoma History
HTS Magnets for Advanced Magnetoplasma Space Propulsion Applications
Plasma rockets are being considered for both Earth-orbit and interplanetary missions because their extremely high exhaust velocity and ability to modulate thrust allow very efficient use of propellant mass. In such rockets, a hydrogen or helium plasma is RF-heated and confined by axial magnetic fields produced by coils around the plasma chamber. HTS coils cooled by the propellant are desirable to increase the energy efficiency of the system. We describe a set of prototype high-temperature superconducting (HTS) coils that are being considered for the VASIMR ( Variable Specific Impulse Magnetoplasma Rocket) thruster proposed for testing on the Radiation Technology Demonstration (RTD) satellite. Since this satellite will be launched by the Space Shuttle, for safety reasons liquid helium will be used as propellant and coolant. The coils must be designed to operate in the space environment at field levels of 1 T. This generates a unique set of requirements. Details of the overall winding geometry and current density, as well as the challenging thermal control aspects associated with a compact, minimum weight design will be discussed.
Date:
July 12, 1999
Creator:
Carte, M. D.; Chang-Diaz, F. R. Squire, J. P. & Schwenterly, S. W.
Object Type:
Article
System:
The UNT Digital Library
The Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 50, No. 141, Ed. 1 Friday, February 12, 1965
Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date:
February 12, 1965
Creator:
Livermore, Edward K.
Object Type:
Newspaper
System:
The Gateway to Oklahoma History