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961.
Lunar base development missions   总被引:1,自引:0,他引:1  
On 20 July 1969, humankind first set foot on our Moon. Since then we have developed the Space Shuttle, explored most of the planets, cooperated in the development of the International Space Station, and expanded our knowledge of the universe through use of systems such as the Hubble Space Telescope and the Mars Pathfinder. After just five human follow-on missions to our Moon, we have returned robotically only twice to orbit, to map the surface and explore for resources.

The indication of the presence of hydrogen concentration at the poles of our Moon found by Lunar Prospector has added a new perspective for groups studying and implementing future lunar missions. Plans for nearterm missions such as the European Space Agency (ESA) “Euromoon 2000”, the Japanese Lunar A and Selene, and the Mitsubishi ”Earthrise 2001” Project, along with follow-on phases to the Lunar Prospector, are the beginning of humankind's return to the Moon. Organizations such as the International Academy of Astronautics have long championed the “Case for an International Lunar Base,” and a vision of a commercially-based lunar program has been outlined by several groups. A Lunar Economic Development Authority (LEDA) promoted by the United Society in Space was promulgated by the filing of articles of incorporation in the state of Colorado on 4 August 1997. This non-profit corporation has as its goal the orderly development of the Moon, through issuance of bonds to international private citizens and business entities who care to invest in its long-term development.

This paper draws from the works of the aforementioned, and specifically from the International Academy of Astronautics Lunar Base Committee, to structure a series of architectures leading toward eventual international commercial colonization of the lunar surface. While the prospect of fully reusable transportation systems utilizing fully developed lunar resources to perpetuate the permanent lunar infrastructure is enticing, this is a goal. We must utilize our current and near-term capabilities to re-initiate human lunar presence, and then build on emerging technologies to strengthen our capabilities. Humankind's return to the Moon is a part of our destiny. We can return in the near future, and then proceed to a commercial, permanent settlement in the 21st century.  相似文献   

962.
A number of studies have selected the sweet potato as a potentially important crop for CELSS. Most hydroponic studies of sweet potatoes have been short term (<80 days). Full term (90 to 150 days) studies of sweet potatoes in hydroponic systems were needed to understand the physiology of storage root enlargement and to evaluate sweet potato production potential for CELSS. Early and late maturing sweet potato varieties were crown in hydroponic systems of different types--static with periodic replacement, flowing with and without recirculation, aggregate, and non-aggregate. In a flowing system with recirculation designed at Tuskegee University using the nutrient film technique (NFT), storage root yields as high as 1790 g were produced with an edible growth rate of up to 66 g m-2 d-1 and a harvest index as high as 89% under greenhouse conditions. Preliminary experiments indicated high yields can be obtained in controlled environmental chambers. Significant cultivar differences were found in all systems studied. Nutritive composition of storage roots and foliage were similar to field-grown plants. The results indicate great potential for sweet potato in CELSS.  相似文献   
963.
Small photocatalytic devices were developed to remove ethylene from closed plant growth units flown in space. The devices utilized sol-gel-derived catalyst pellets of zirconia-titania. This study was undertaken to understand the significance of different factors on the photocatalytic activity of the catalyst. Increasing reaction temperatures and decreasing humidity of the air significantly increased oxidation of ethylene. The quantity of ethylene oxidized per unit time increased linearly with increasing flow rates, and increasing concentrations of ethylene. Zirconia-titania pellet size and heel depth had little effect on oxidation of ethylene. Platinizing the zirconia-titania significantly increased ethylene oxidation. The catalyst was found to absorb large quantities of water when the humidity of the air stream was elevated and this greatly decreased catalytic activity.  相似文献   
964.
The transport properties of galactic cosmic rays (GCR) in the atmosphere, material structures, and human body (self-shielding) are of interest in risk assessment for supersonic and subsonic aircraft and for space travel in low-Earth orbit and on interplanetary missions. Nuclear reactions, such as knockout and fragmentation, present large modifications of particle type and energies of the galactic cosmic rays in penetrating materials. We make an assessment of the current nuclear reaction models and improvements in these model for developing required transport code data bases. A new fragmentation data base (QMSFRG) based on microscopic models is compared to the NUCFRG2 model and implications for shield assessment made using the HZETRN radiation transport code. For deep penetration problems, the build-up of light particles, such as nucleons, light clusters and mesons from nuclear reactions in conjunction with the absorption of the heavy ions, leads to the dominance of the charge Z = 0, 1, and 2 hadrons in the exposures at large penetration depths. Light particles are produced through nuclear or cluster knockout and in evaporation events with characteristically distinct spectra which play unique roles in the build-up of secondary radiation's in shielding. We describe models of light particle production in nucleon and heavy ion induced reactions and make an assessment of the importance of light particle multiplicity and spectral parameters in these exposures.  相似文献   
965.
The space sector has frequently been confronted with cost overruns, with a negative impact on its management reputation. There are many reasons for this effect, the main one being that space development contracts are unique and often do not allow proper cost benchmarking. On the other hand, tools have been developed to minimise this effect and it is important to train future space managers in applying such tools. In the International Space University, such methods are illustrated with workshops, which aim to be as close as possible to reality. This article will describe the different techniques, memo-technically called the 5C approach here, and develop the use of a computerised tool, PRICE, to support these techniques in the different phases of the projects.  相似文献   
966.
For the purposes of planetary protection, a series of experiments were performed to answer a long-standing question about the potential of bacterial contamination of interplanetary spacecraft from liquid hydrazine. Spores of Bacillus atrophaeus (ATCC No. 9372, also known as Bacillus subtilis var. niger, and BSN) were exposed to hydrazine and survivors were enumerated using the NASA standard planetary protection pour plate assay. Results indicate that bulk hydrazine rocket propellant may be considered free of living bacterial cells for planetary protection compliance.  相似文献   
967.
First Results of the THEMIS Search Coil Magnetometers   总被引:1,自引:0,他引:1  
We present the first data from the THEMIS Search Coil Magnetometers (SCM), taken between March and June 2007 while the THEMIS constellation apogee moved from the duskside toward the dawnside. Data reduction, especially the SCM calibration method and spurious noise reduction process, is described. The signatures of magnetic fluctuations in key magnetospheric regions such as the bow shock, the magnetopause and the magnetotail during a substorm, are described. We also discuss the role that magnetic fluctuations could play in plasma transport, acceleration and heating.  相似文献   
968.
Successful execution of a program and full satisfaction of the customer's requirements is a challenge for any contractor. Raytheon Company responds to this challenge by following a proven program execution methodology. The methodology includes all program aspects from financial planning to engineering to validation and test. This discusses the engineering team and the role of the mechanical engineer. A radar system is ultimately an assembly of advanced electronics and software. However, the design, fabrication, assembly, integration, and test Of this complex system requires a coherent multi-disciplinary approach. Raytheon, like many contractors, chooses to assemble an integrated product team (IPT) including all engineering disciplines. Mechanical engineering is integral to satisfying performance requirements, performing preliminary and detailed design, transition of the design to manufacturing, and implementation of the hardware in the field. During definition, mechanical engineering assists fundamental architecture development, conceptual design, and requirements development which precludes issues that are sometimes ignored to the detriment of many programs. These design issues include environmental protection, structural stiffness to meet deflection requirements, cooling system capacity to properly remove dissipated heat, manufacturabilit3' to control cost, maintainability to enable repair in the field, and transportability. Recognizing and trading off these issues early greatly increases the Probability Of satisfying customer objectives. This discusses the approach Raytheon is taking to ensure an overall multi-disciplinary solution to our design challenges from the perspective of the mechanical engineer.  相似文献   
969.
We have examined the ionospheric plasma irregularities that were recorded by using three ground-based receivers of the global positioning system (GPS) located at Brazilian longitudes during the period of a complete solar cycle, 1995–2005. The statistic results show that ionospheric irregularities are very easy to occur in December solstice months but rare to occur in June solstice months. Besides, the occurrence rates of irregularities in both December and June solstice months are little dependent on solar activity. However, in equinoctial months, the development of irregularities is obviously dependent on solar activity. There is a new finding in this study that if strong irregularities are distinguished from moderate ones, their occurrence rates would increase with solar activity during the December solstice months.  相似文献   
970.
Living organisms, especially plants, show some plasticity in their overall development, usually as a response to the external environment. Plasticity may apply not only to the external form of organisms but also to their physiology as well as to the detailed structure of their genome. A further example of plasticity may be developmental instability, where anomalous development seems to appear spontaneously, probably as a result of some transient environmental perturbation. Whether the absence of gravity would have sufficient impact on any living process to evoke a specific course of plastic development is unknown, though it is possible that in certain circumstances special forms, or 'agravimorphs', could be produced. Through such new forms, it should be possible to identify processes required for development in which 1 x g gravity is a necessary participant.  相似文献   
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