10 383 résultats
1987779992PN. New. 1987. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
1987779631PN. New. 1987. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
1988783327PN. New. 1988. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
1993263286PN. New. 1993. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1993263285PN. New. 1993. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1993266813PN. New. 1993. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1988789183PN. New. 1988. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
1987780464PN. New. 1987. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
1988783342PN. New. 1988. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
1990233483PN. New. 1990. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1993261664PN. New. 1993. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1988781574PN. New. 1988. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
1991242313PN. New. 1991. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1993262052PN. New. 1993. Soft Cover. Date is original print. This is a reprint edition . PN paperback
20011337602PN. New. 2001. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1990234158PN. New. 1990. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1991250932PN. New. 1991. Soft Cover. Date is original print. This is a reprint edition . PN paperback
1988782029PN. New. 1988. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
1987780270PN. New. 1987. Soft Cover. Date is original print. This is a reprint edition. . PN paperback
199144049Washington DC: NASA 1991. very good. 28 cm 533 & 537 wraps 2-vol. set illus. diagrams references. NASA paperback
201091089Washington DC: The National Academies Press 2010. Presumed First Edition First printing. Wraps. Very good. xvii 1 134 pages. Footnotes. Illustrations Tables Figures Photographs some with color. References. Bibliography. Appendixes. Glossary and Selected Acronyms. The United States spends approximately $4 million each year searching for near-Earth objects NEOs. The objective is to detect those that may collide with Earth. The majority of this funding supports the operation of several observatories that scan the sky searching for NEOs. This however is insufficient in detecting the majority of NEOs that may present a tangible threat to humanity. A significantly smaller amount of funding supports ways to protect the Earth from such a potential collision or “mitigation.†In 2005 a Congressional mandate called for NASA to detect 90 percent of NEOs with diameters of 140 meters or greater by 2020. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies identifies the need for detection of objects as small as 30 to 50 meters as these can be highly destructive. The book explores four main types of mitigation including civil defense “slow push†or “pull†methods kinetic impactors and nuclear explosions. It also asserts that responding effectively to hazards posed by NEOs requires national and international cooperation. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies is a useful guide for scientists astronomers policy makers and engineers. The Table of Contents: Front Matter; Summary; 1 Introduction; 2 Risk Analysis; 3 Survey and Detection of Near-Earth Objects; 4 Characterization; 5 Mitigation; 6 Research; 7 National and International Coordination and Collaboration; 8 Optimal Approaches; Appendixes: Appendix A: Independent Cost Assessment; Appendix B: Letter of Request; Appendix C: Committee Panel and Staff Biographical Information; Appendix D: Minority Opinion - Mark Boslough Mitigation Panel Member; Appendix E: Glossary and Selected Acronyms. <br /> Planetary defense is the organized global effort to detect track and mitigate potential asteroid or comet impacts on Earth. Coordinated by agencies like NASA's Planetary Defense Coordination Office PDCO it involves surveying for Near-Earth Objects NEOs to prevent catastrophic natural disasters. Strategies include detection characterization and deflection techniques like kinetic impactors. Key Components of Planetary Defense: Detection & Tracking: Astronomers use telescopes to find and monitor NEOs forecasting their paths to identify risks; and Characterization: Scientists analyze the size shape composition and spin rate of hazardous objects. Mitigation/Deflection: Kinetic Impactors: Crashing a spacecraft into an asteroid to alter its path e.g. NASA's DART mission; Nuclear Explosions: An option for large threats or short warning times; "Slow Push/Pull" Methods: Utilizing gravity tractors or laser ablation to gently change an object's orbit. Organizations and Partnerships: NASA & PDCO: Leads US efforts and coordinates with international partners including the International Asteroid Warning Network IAWN and Space Mission Planning Advisory Group SMPAG. Johns Hopkins Applied Physics Laboratory APL: Involved in developing mission technologies: The Planetary Society: Supports research and advocacy for planetary defense. Key Takeaways: Asteroid impacts are rare but potentially devastating. It is considered the only natural disaster humanity could potentially avoid. The goal is to detect threats early to allow for smaller manageable deflections. The National Academies Press paperback
1996287662PN. New. 1996. Soft Cover. Date is original print. This is a reprint edition . PN paperback
199138202Washington DC: NASA 1991. First Edition. First Printing. good. 28 cm 420 & 375 2-vol. set wraps illus. references some wear scuffing creasing & soiling to covers. NASA conference publication 3109. Mailing label on rear covers. NASA paperback
191936839Washington DC: GPO 1919. fair. 446 illus. figures tables index pp. 5-8 had become separated and have been reglued boards somewhat worn and soiled. Captures the state of aviation medicine at the end of World War I. GPO hardcover
4473Between 1931 and 1934; all on letterhead of the Royal Aeronautical Society of which Pritchard was secretary. Novelist and writer on aeronautics 1885-1968. All items one page quarto. As a whole good though grubby but some items with pin holes closed tears etc. Most bearing the R.S.A. stamp and some docketed. Three items with enclosures. The items are dry communications relating to the arranging of R.A.S. lectures at the R.S.A. premises at the Adelphi except for one item 12 May 1931 beginning 'I have received a number of letters from various members of the Society and others complaining of the lantern and cinema projector at the Royal Society of Arts . under the impression that we own both these and that we should get better instruments.' An enclosed copy of a letter from Gerald Merton 7 May 1931 begins 'I have often intended to convey you a grouse I have. At last I summon enough energy to write it.' This describes the lantern show as 'the worst effort I have ever come across . For learned societies of such standing to use such an apparatus is a disgrace.' Between 1931 and 1934; all on letterhead of the Royal Aeronautical Society, of which Pritchard was secretary. unknown