Power Options For Lunar Exploration
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Author | : Allan C. Schell |
Publisher | : |
Total Pages | : 68 |
Release | : 1966 |
Genre | : Antennas (Electronics) |
ISBN | : |
The multiplate technique is a method of antenna design that is intended to allow the economical construction of very large antennas. The aperture area is divided into a large number of reflectors that can be adjusted in orientation and height. These plates are positioned so that energy from a desired direction is redirected to add at the focus. In this paper an analysis of the effects caused by the interstices in a multiple plate antenna is presented. The loss due to gaps and shadowing, the variation in effective receiving cross section, and the radiation pattern are determined. The bandwidth properties of this type of antenna are analyzed, and methods for reducing the effect of frequency dispersion on the pattern are presented. A short discussion of the components of a 2500-ft multiplate antenna is included. An experimental program of measurement has determined the radiation pattern, the efficiency and the relative change of gain and antenna temperature versus beam angle of a test section of a multiplate antenna. The effect of the interstices in the reflecting surface produced grating lobes of approximately -20 dB and an additional temperature component that varied from 20K - 65K depending on the beam angle. (Author).
Author | : National Research Council |
Publisher | : National Academies Press |
Total Pages | : 68 |
Release | : 2009-08-14 |
Genre | : Science |
ISBN | : 0309138574 |
Spacecraft require electrical energy. This energy must be available in the outer reaches of the solar system where sunlight is very faint. It must be available through lunar nights that last for 14 days, through long periods of dark and cold at the higher latitudes on Mars, and in high-radiation fields such as those around Jupiter. Radioisotope power systems (RPSs) are the only available power source that can operate unconstrained in these environments for the long periods of time needed to accomplish many missions, and plutonium-238 (238Pu) is the only practical isotope for fueling them. Plutonium-238 does not occur in nature. The committee does not believe that there is any additional 238Pu (or any operational 238Pu production facilities) available anywhere in the world.The total amount of 238Pu available for NASA is fixed, and essentially all of it is already dedicated to support several pending missions-the Mars Science Laboratory, Discovery 12, the Outer Planets Flagship 1 (OPF 1), and (perhaps) a small number of additional missions with a very small demand for 238Pu. If the status quo persists, the United States will not be able to provide RPSs for any subsequent missions.
Author | : National Research Council |
Publisher | : National Academies Press |
Total Pages | : 376 |
Release | : 2012-06-07 |
Genre | : Science |
ISBN | : 0309253624 |
NASA's Office of the Chief Technologist (OCT) has begun to rebuild the advanced space technology program in the agency with plans laid out in 14 draft technology roadmaps. It has been years since NASA has had a vigorous, broad-based program in advanced space technology development and its technology base has been largely depleted. However, success in executing future NASA space missions will depend on advanced technology developments that should already be underway. Reaching out to involve the external technical community, the National Research Council (NRC) considered the 14 draft technology roadmaps prepared by OCT and ranked the top technical challenges and highest priority technologies that NASA should emphasize in the next 5 years. This report provides specific guidance and recommendations on how the effectiveness of the technology development program managed by OCT can be enhanced in the face of scarce resources.
Author | : Gary L. Bennett |
Publisher | : |
Total Pages | : 32 |
Release | : 1991 |
Genre | : Electric power |
ISBN | : |
Author | : National Research Council |
Publisher | : National Academies Press |
Total Pages | : 464 |
Release | : 2012-01-30 |
Genre | : Science |
ISBN | : 0309163846 |
More than four decades have passed since a human first set foot on the Moon. Great strides have been made in our understanding of what is required to support an enduring human presence in space, as evidenced by progressively more advanced orbiting human outposts, culminating in the current International Space Station (ISS). However, of the more than 500 humans who have so far ventured into space, most have gone only as far as near-Earth orbit, and none have traveled beyond the orbit of the Moon. Achieving humans' further progress into the solar system had proved far more difficult than imagined in the heady days of the Apollo missions, but the potential rewards remain substantial. During its more than 50-year history, NASA's success in human space exploration has depended on the agency's ability to effectively address a wide range of biomedical, engineering, physical science, and related obstacles-an achievement made possible by NASA's strong and productive commitments to life and physical sciences research for human space exploration, and by its use of human space exploration infrastructures for scientific discovery. The Committee for the Decadal Survey of Biological and Physical Sciences acknowledges the many achievements of NASA, which are all the more remarkable given budgetary challenges and changing directions within the agency. In the past decade, however, a consequence of those challenges has been a life and physical sciences research program that was dramatically reduced in both scale and scope, with the result that the agency is poorly positioned to take full advantage of the scientific opportunities offered by the now fully equipped and staffed ISS laboratory, or to effectively pursue the scientific research needed to support the development of advanced human exploration capabilities. Although its review has left it deeply concerned about the current state of NASA's life and physical sciences research, the Committee for the Decadal Survey on Biological and Physical Sciences in Space is nevertheless convinced that a focused science and engineering program can achieve successes that will bring the space community, the U.S. public, and policymakers to an understanding that we are ready for the next significant phase of human space exploration. The goal of this report is to lay out steps and develop a forward-looking portfolio of research that will provide the basis for recapturing the excitement and value of human spaceflight-thereby enabling the U.S. space program to deliver on new exploration initiatives that serve the nation, excite the public, and place the United States again at the forefront of space exploration for the global good.
Author | : Gary L. Bennett |
Publisher | : |
Total Pages | : 32 |
Release | : 1991 |
Genre | : Lunar bases |
ISBN | : |
Author | : Harrison Schmitt |
Publisher | : Springer Science & Business Media |
Total Pages | : 346 |
Release | : 2007-12-28 |
Genre | : Science |
ISBN | : 0387310649 |
Former NASA Astronaut Harrison Schmitt advocates a private, investor-based approach to returning humans to the Moon—to extract Helium 3 for energy production, to use the Moon as a platform for science and manufacturing, and to establish permanent human colonies there in a kind of stepping stone community on the way to deeper space. With governments playing a supporting role—just as they have in the development of modern commercial aeronautics and agricultural production—Schmitt believes that a fundamentally private enterprise is the only type of organization capable of sustaining such an effort and, eventually, even making it pay off.
Author | : Norman R. Schulze |
Publisher | : |
Total Pages | : 496 |
Release | : 1991 |
Genre | : Nuclear fusion |
ISBN | : |
Author | : Wendell W. Mendell |
Publisher | : |
Total Pages | : 888 |
Release | : 1985 |
Genre | : Science |
ISBN | : |
Author | : |
Publisher | : |
Total Pages | : 188 |
Release | : 1992 |
Genre | : Natural resources |
ISBN | : |