A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs

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Author :
Publisher : National Academies Press
ISBN 13 : 0309102472
Total Pages : 288 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs by : National Research Council

Download or read book A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs written by National Research Council and published by National Academies Press. This book was released on 2007-01-14 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rocket and air-breathing propulsion systems are the foundation on which planning for future aerospace systems rests. A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs assesses the existing technical base in these areas and examines the future Air Force capabilities the base will be expected to support. This report also defines gaps and recommends where future warfighter capabilities not yet fully defined could be met by current science and technology development plans.

After LM

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Publisher :
ISBN 13 : 9780578622729
Total Pages : 260 pages
Book Rating : 4.6/5 (227 download)

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Book Synopsis After LM by : John F. Connolly

Download or read book After LM written by John F. Connolly and published by . This book was released on 2020 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Beyond Earth

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Publisher : National Aeronautis & Space Administration
ISBN 13 :
Total Pages : 396 pages
Book Rating : 4.:/5 (318 download)

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Book Synopsis Beyond Earth by : Asif A. Siddiqi

Download or read book Beyond Earth written by Asif A. Siddiqi and published by National Aeronautis & Space Administration. This book was released on 2018 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a completely updated and revised version of a monograph published in 2002 by the NASA History Office under the original title Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes, 1958-2000. This new edition not only adds all events in robotic deep space exploration after 2000 and up to the end of 2016, but it also completely corrects and updates all accounts of missions from 1958 to 2000--Provided by publisher.

Recapturing a Future for Space Exploration

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Publisher : National Academies Press
ISBN 13 : 0309163846
Total Pages : 464 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis Recapturing a Future for Space Exploration by : National Research Council

Download or read book Recapturing a Future for Space Exploration written by National Research Council and published by National Academies Press. This book was released on 2012-01-30 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

NASA System Safety Handbook

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Publisher :
ISBN 13 : 9781470116910
Total Pages : 118 pages
Book Rating : 4.1/5 (169 download)

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Book Synopsis NASA System Safety Handbook by : Homayoon Dezfuli

Download or read book NASA System Safety Handbook written by Homayoon Dezfuli and published by . This book was released on 2012-02-27 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: System safety is the application of engineering and management principles, criteria, and techniques to optimize safety within the constraints of operational effectiveness, time, and cost throughout all phases of the system life cycle. System safety is to safety as systems engineering is to engineering. When performing appropriate analysis, the evaluation is performed holistically by tying into systems engineering practices and ensuring that system safety has an integrated system-level perspective.The NASA System Safety Handbook presents the overall framework for System Safety and provides the general concepts needed to implement the framework. The treatment addresses activities throughout the system life cycle to assure that the system meets safety performance requirements and is as safe as reasonably practicable.This handbook is intended for project management and engineering teams and for those with review and oversight responsibilities. It can be used both in a forward-thinking mode to promote the development of safe systems, and in a retrospective mode to determine whether desired safety objectives have been achieved.The topics covered in this volume include general approaches for formulating a hierarchy of safety objectives, generating a corresponding hierarchical set of safety claims, characterizing the system safety activities needed to provide supporting evidence, and presenting a risk-informed safety case that validates the claims. Volume 2, to be completed in 2012, will provide specific guidance on the conduct of the major system safety activities and the development of the evidence.

AU-18 Space Primer

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Publisher : CreateSpace
ISBN 13 : 9781478393559
Total Pages : 354 pages
Book Rating : 4.3/5 (935 download)

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Book Synopsis AU-18 Space Primer by : Air Command Staff College

Download or read book AU-18 Space Primer written by Air Command Staff College and published by CreateSpace. This book was released on 2012-08-01 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: The US National Space Policy released by the president in 2006 states that the US government should "develop space professionals." As an integral part of that endeavor, "AU-18, Space Primer", provides to the joint war fighter an unclassified resource for understanding the capabilities, organizations, and operations of space forces. This primer is a useful tool both for individuals who are not "space aware"-unacquainted with space capabilities, organizations, and operations-and for those who are "space aware," especially individuals associated with the space community, but not familiar with space capabilities, organizations, and operations outside their particular areas of expertise. It is your guide and your invitation to all the excitement and opportunity of space. Last published in 1993, this updated version of the Space Primer has been made possible by combined efforts of the Air Command and Staff College's academic year 2008 "Jointspacemindedness" and "Operational Space" research seminars, as well as select members of the academic year 2009 "Advanced Space" research seminar. Air university Press.

The Test and Launch Control Technology for Launch Vehicles

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Publisher : Springer
ISBN 13 : 9811087121
Total Pages : 255 pages
Book Rating : 4.8/5 (11 download)

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Book Synopsis The Test and Launch Control Technology for Launch Vehicles by : Zhengyu Song

Download or read book The Test and Launch Control Technology for Launch Vehicles written by Zhengyu Song and published by Springer. This book was released on 2018-04-19 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents technologies and solutions related to the test and launch control of rockets and other vehicles, and offers the first comprehensive and systematic introduction to the contributions of the Chinese Long March (Chang Zheng in Chinese, or abbreviated as CZ) rockets in this field. Moreover, it discusses the role of this technology in responsive, reliable, and economical access to space, which is essential for the competitiveness of rockets. The need for rapid development of the aerospace industry for both governmental and commercial projects is addressed. This book is a valuable reference resource for practitioners, and many examples and resources are included, not only from Chinese rockets but also from many other vehicles. It covers guidelines, technologies, and solutions on testing and launch control before rocket takeoff, covering equipment-level testing, system-level testing, simulation tests, etc.

Moon

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Publisher : Springer Science & Business Media
ISBN 13 : 3642279694
Total Pages : 771 pages
Book Rating : 4.6/5 (422 download)

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Book Synopsis Moon by : Viorel Badescu

Download or read book Moon written by Viorel Badescu and published by Springer Science & Business Media. This book was released on 2012-03-22 with total page 771 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Earth has limited material and energy resources. Further development of the humanity will require going beyond our planet for mining and use of extraterrestrial mineral resources and search of power sources. The exploitation of the natural resources of the Moon is a first natural step on this direction. Lunar materials may contribute to the betterment of conditions of people on Earth but they also may be used to establish permanent settlements on the Moon. This will allow developing new technologies, systems and flight operation techniques to continue space exploration. In fact, a new branch of human civilization could be established permanently on Moon in the next century. But, meantime, an inventory and proper social assessment of Moon’s prospective energy and material resources is required. This book investigates the possibilities and limitations of various systems supplying manned bases on Moon with energy and other vital resources. The book collects together recent proposals and innovative options and solutions. It is a useful source of condensed information for specialists involved in current and impending Moon-related activities and a good starting point for young researchers.

Automated Rendezvous and Docking of Spacecraft

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Publisher : Cambridge University Press
ISBN 13 : 1139440683
Total Pages : 517 pages
Book Rating : 4.1/5 (394 download)

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Book Synopsis Automated Rendezvous and Docking of Spacecraft by : Wigbert Fehse

Download or read book Automated Rendezvous and Docking of Spacecraft written by Wigbert Fehse and published by Cambridge University Press. This book was released on 2003-11-13 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: The definitive reference for space engineers on rendezvous and docking/berthing (RVD/B) related issues, this book answers key questions such as: How does the docking vehicle accurately approach the target spacecraft? What technology is needed aboard the spacecraft to perform automatic rendezvous and docking, and what systems are required by ground control to supervise this process? How can the proper functioning of all rendezvous-related equipment, systems and operations be verified before launch? The book provides an overview of the major issues governing approach and mating strategies, and system concepts for rendezvous and docking/berthing. These issues are described and explained such that aerospace engineers, students and even newcomers to the field can acquire a basic understanding of RVD/B. The author would like to extend his thanks to Dr Shufan Wu, GNC specialist and translator of the book's Chinese edition, for his help in the compilation of these important errata.

Logistics 4.0

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Publisher : CRC Press
ISBN 13 : 1000245101
Total Pages : 369 pages
Book Rating : 4.0/5 (2 download)

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Book Synopsis Logistics 4.0 by : Turan Paksoy

Download or read book Logistics 4.0 written by Turan Paksoy and published by CRC Press. This book was released on 2020-12-17 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: Industrial revolutions have impacted both, manufacturing and service. From the steam engine to digital automated production, the industrial revolutions have conduced significant changes in operations and supply chain management (SCM) processes. Swift changes in manufacturing and service systems have led to phenomenal improvements in productivity. The fast-paced environment brings new challenges and opportunities for the companies that are associated with the adaptation to the new concepts such as Internet of Things (IoT) and Cyber Physical Systems, artificial intelligence (AI), robotics, cyber security, data analytics, block chain and cloud technology. These emerging technologies facilitated and expedited the birth of Logistics 4.0. Industrial Revolution 4.0 initiatives in SCM has attracted stakeholders’ attentions due to it is ability to empower using a set of technologies together that helps to execute more efficient production and distribution systems. This initiative has been called Logistics 4.0 of the fourth Industrial Revolution in SCM due to its high potential. Connecting entities, machines, physical items and enterprise resources to each other by using sensors, devices and the internet along the supply chains are the main attributes of Logistics 4.0. IoT enables customers to make more suitable and valuable decisions due to the data-driven structure of the Industry 4.0 paradigm. Besides that, the system’s ability of gathering and analyzing information about the environment at any given time and adapting itself to the rapid changes add significant value to the SCM processes. In this peer-reviewed book, experts from all over the world, in the field present a conceptual framework for Logistics 4.0 and provide examples for usage of Industry 4.0 tools in SCM. This book is a work that will be beneficial for both practitioners and students and academicians, as it covers the theoretical framework, on the one hand, and includes examples of practice and real world.

On Integrating Unmanned Aircraft Systems into the National Airspace System

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Author :
Publisher : Springer Science & Business Media
ISBN 13 : 9400724799
Total Pages : 318 pages
Book Rating : 4.4/5 (7 download)

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Book Synopsis On Integrating Unmanned Aircraft Systems into the National Airspace System by : Konstantinos Dalamagkidis

Download or read book On Integrating Unmanned Aircraft Systems into the National Airspace System written by Konstantinos Dalamagkidis and published by Springer Science & Business Media. This book was released on 2011-10-05 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents, in a comprehensive way, current unmanned aviation regulation, airworthiness certification, special aircraft categories, pilot certification, federal aviation requirements, operation rules, airspace classes and regulation development models. It discusses unmanned aircraft systems levels of safety derived mathematically based on the corresponding levels for manned aviation. It provides an overview of the history and current status of UAS airworthiness and operational regulation worldwide. Existing regulations have been developed considering the need for a complete regulatory framework for UAS. It focuses on UAS safety assessment and functional requirements, achieved in terms of defining an “Equivalent Level of Safety”, or ELOS, with that of manned aviation, specifying what the ELOS requirement entails for UAS regulations. To accomplish this, the safety performance of manned aviation is first evaluated, followed by a novel model to derive reliability requirements for achieving target levels of safety (TLS) for ground impact and mid-air collision accidents.It discusses elements of a viable roadmap leading to UAS integration in to the NAS. For this second edition of the book almost all chapters include major updates and corrections. There is also a new appendix chapter.

X-Planes from the X-1 to the X-60

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Author :
Publisher : Springer Nature
ISBN 13 : 3030863980
Total Pages : 183 pages
Book Rating : 4.0/5 (38 download)

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Book Synopsis X-Planes from the X-1 to the X-60 by : Michael H. Gorn

Download or read book X-Planes from the X-1 to the X-60 written by Michael H. Gorn and published by Springer Nature. This book was released on 2022-01-01 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foreword by Dr. Roger D. Launius, Former NASA Chief Historian For the past 75 years, the U.S. government has invested significant time and money into advanced aerospace research, as evidenced by its many experimental X-plane aircraft and rockets. NASA's X-Planes asks a simple question: What have we gained from it all? To answer this question, the authors provide a comprehensive overview of the X-plane’s long history, from the 1946 X-1 to the modern X-60. The chapters describe not just the technological evolution of these models, but also the wider story of politics, federal budgets, and inter-agency rivalries surrounding them. The book is organized into two sections, with the first covering the operational X-planes that symbolized the Cold War struggle between the U.S. and the U.S.S.R, and the second section surveying post-Cold War aircraft and spacecraft. Featuring dozens of original illustrations of X-plane cross-sections, in-flight profiles, close-ups, and more, this book will educate general readers and specialists alike.

Chemical Engineering Design

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Publisher : Elsevier
ISBN 13 : 0080966608
Total Pages : 1321 pages
Book Rating : 4.0/5 (89 download)

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Book Synopsis Chemical Engineering Design by : Gavin Towler

Download or read book Chemical Engineering Design written by Gavin Towler and published by Elsevier. This book was released on 2012-01-25 with total page 1321 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical Engineering Design, Second Edition, deals with the application of chemical engineering principles to the design of chemical processes and equipment. Revised throughout, this edition has been specifically developed for the U.S. market. It provides the latest US codes and standards, including API, ASME and ISA design codes and ANSI standards. It contains new discussions of conceptual plant design, flowsheet development, and revamp design; extended coverage of capital cost estimation, process costing, and economics; and new chapters on equipment selection, reactor design, and solids handling processes. A rigorous pedagogy assists learning, with detailed worked examples, end of chapter exercises, plus supporting data, and Excel spreadsheet calculations, plus over 150 Patent References for downloading from the companion website. Extensive instructor resources, including 1170 lecture slides and a fully worked solutions manual are available to adopting instructors. This text is designed for chemical and biochemical engineering students (senior undergraduate year, plus appropriate for capstone design courses where taken, plus graduates) and lecturers/tutors, and professionals in industry (chemical process, biochemical, pharmaceutical, petrochemical sectors). New to this edition: - Revised organization into Part I: Process Design, and Part II: Plant Design. The broad themes of Part I are flowsheet development, economic analysis, safety and environmental impact and optimization. Part II contains chapters on equipment design and selection that can be used as supplements to a lecture course or as essential references for students or practicing engineers working on design projects. - New discussion of conceptual plant design, flowsheet development and revamp design - Significantly increased coverage of capital cost estimation, process costing and economics - New chapters on equipment selection, reactor design and solids handling processes - New sections on fermentation, adsorption, membrane separations, ion exchange and chromatography - Increased coverage of batch processing, food, pharmaceutical and biological processes - All equipment chapters in Part II revised and updated with current information - Updated throughout for latest US codes and standards, including API, ASME and ISA design codes and ANSI standards - Additional worked examples and homework problems - The most complete and up to date coverage of equipment selection - 108 realistic commercial design projects from diverse industries - A rigorous pedagogy assists learning, with detailed worked examples, end of chapter exercises, plus supporting data and Excel spreadsheet calculations plus over 150 Patent References, for downloading from the companion website - Extensive instructor resources: 1170 lecture slides plus fully worked solutions manual available to adopting instructors

Parachute Recovery Systems

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Publisher :
ISBN 13 :
Total Pages : 524 pages
Book Rating : 4.0/5 ( download)

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Book Synopsis Parachute Recovery Systems by : Theo W. Knacke

Download or read book Parachute Recovery Systems written by Theo W. Knacke and published by . This book was released on 1992 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this manual is to provide recovery system engineers in government and industry with tools to evaluate, analyze, select, and design parachute recovery systems. These systems range from simple, one-parachute assemblies to multiple-parachute systems, and may include equipment for impact attenuation, flotation, location, retrieval, and disposition. All system aspects are discussed, including the need for parachute recovery, the selection of the most suitable recovery system concept, concept analysis, parachute performance, force and stress analysis, material selection, parachute assembly and component design, and manufacturing. Experienced recovery system engineers will find this publication useful as a technical reference book; recent college graduates will find it useful as a textbook for learning about parachutes and parachute recovery systems; and technicians with extensive practical experience will find it useful as an engineering textbook that includes a chapter on parachute- related aerodynamics. In this manual, emphasis is placed on aiding government employees in evaluating and supervising the design and application of parachute systems. The parachute recovery system uses aerodynamic drag to decelerate people and equipment moving in air from a higher velocity to a lower velocity and to a safe landing. This lower velocity is known as rate of descent, landing velocity, or impact velocity, and is determined by the following requirements: (1) landing personnel uninjured and ready for action, (2) landing equipment and air vehicles undamaged and ready for use or refurbishment, and (3) impacting ordnance at a preselected angle and velocity.

SpaceX's Dragon: America's Next Generation Spacecraft

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Publisher : Springer
ISBN 13 : 3319215159
Total Pages : 202 pages
Book Rating : 4.3/5 (192 download)

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Book Synopsis SpaceX's Dragon: America's Next Generation Spacecraft by : Erik Seedhouse

Download or read book SpaceX's Dragon: America's Next Generation Spacecraft written by Erik Seedhouse and published by Springer. This book was released on 2015-11-04 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dragon V2 is a futuristic vehicle that not only provides a means for NASA to transport its astronauts to the orbiting outpost but also advances SpaceX’s core objective of reusability. A direct descendant of Dragon, Dragon V2 can be retrieved, refurbished and re-launched. It is a spacecraft with the potential to completely revolutionize the economics of an industry where equipment costing hundreds of millions of dollars is routinely discarded after a single use. It was presented by SpaceX CEO Elon Musk in May 2014 as the spaceship that will carry NASA astronauts to the International Space Station as soon as 2016. SpaceX’s Dragon – America’s Next Generation Spacecraft describes the extraordinary feats of engineering and human achievement that have placed this revolutionary spacecraft at the forefront of the launch industry and positioned it as the precursor for ultimately transporting humans to Mars. It describes the design and development of Dragon, provides mission highlights of the first six Commercial Resupply Missions, and explains how Musk hopes to eventually colonize Mars.

Nasa Systems Engineering Handbook - Nasa Sp-2016-6105 Rev2

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Author :
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781979381475
Total Pages : 298 pages
Book Rating : 4.3/5 (814 download)

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Book Synopsis Nasa Systems Engineering Handbook - Nasa Sp-2016-6105 Rev2 by : National Aeronautics and Space Administration

Download or read book Nasa Systems Engineering Handbook - Nasa Sp-2016-6105 Rev2 written by National Aeronautics and Space Administration and published by Createspace Independent Publishing Platform. This book was released on 2017-11-03 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook, "NASA Systems Engineering Handbook," is intended to provide general guidance and information on systems engineering that will be useful to the NASA community. It provides a generic description of Systems Engineering (SE) as it should be applied throughout NASA. A goal of the handbook is to increase awareness and consis¬tency across the Agency and advance the practice of SE. This handbook provides perspectives relevant to NASA and data particular to NASA. This handbook describes systems engineering best practices that should be incorporated in the development and implementation of large and small NASA programs and projects. The engineering of NASA systems requires a systematic and disciplined set of processes that are applied recursively and iteratively for the design, development, operation, maintenance, and closeout of systems throughout the life cycle of the programs and projects. The scope of this handbook includes systems engineering functions regardless of whether they are performed by a manager or an engineer, in-house or by a contractor.

NASA's First 50 Years Historical Perspectives

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Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781470024758
Total Pages : 776 pages
Book Rating : 4.0/5 (247 download)

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Book Synopsis NASA's First 50 Years Historical Perspectives by : Steven J. Dick

Download or read book NASA's First 50 Years Historical Perspectives written by Steven J. Dick and published by Createspace Independent Publishing Platform. This book was released on 2010-08-20 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fifty years after the founding of NASA, from 28 to 29 October 2008, the NASA History Division convened a conference whose purpose was a scholarly analysis of NASA's first 50 years. Over two days at NASA Headquarters, historians and policy analysts discussed NASA's role in aeronautics, human spaceflight, exploration, space science, life science, and Earth science, as well as crosscutting themes ranging from space access to international relations in space and NASA's interaction with the public. The speakers were asked to keep in mind the following questions: What are the lessons learned from the first 50 years? What is NASA's role in American culture and in the history of exploration and discovery? What if there had never been a NASA? Based on the past, does NASA have a future? The results of those papers, elaborated and fully referenced, are found in this 50th anniversary volume. The reader will find here, instantiated in the complex institution that is NASA, echoes of perennial themes elaborated in an earlier volume, Critical Issues in the History of Spaceflight. The conference culminated a year of celebrations, beginning with an October 2007 conference celebrating the 50th anniversary of the Space Age and including a lecture series, future forums, publications, a large presence at the Smithsonian Folklife Festival, and numerous activities at NASA's 10 Centers and venues around the country. It took place as the Apollo 40th anniversaries began, ironically still the most famous of NASA's achievements, even in the era of the Space Shuttle, International Space Station (ISS), and spacecraft like the Mars Exploration Rovers (MERs) and the Hubble Space Telescope. And it took place as NASA found itself at a major crossroads, for the first time in three decades transitioning, under Administrator Michael Griffin, from the Space Shuttle to a new Ares launch vehicle and Orion crew vehicle capable of returning humans to the Moon and proceeding to Mars in a program known as Constellation. The Space Shuttle, NASA's launch system since 1981, was scheduled to wind down in 2010, freeing up funds for the new Ares launch vehicle. But the latter, even if it moved forward at all deliberate speed, would not be ready until 2015, leaving the unsettling possibility that for at least five years the United States would be forced to use the Russian Soyuz launch vehicle and spacecraft as the sole access to the ISS in which the United States was the major partner. The presidential elections a week after the conference presaged an imminent presidential transition, from the Republican administration of George W. Bush to (as it turned out) the Democratic presidency of Barack Obama, with all the uncertainties that such transitions imply for government programs. The uncertainties for NASA were even greater, as Michael Griffin departed with the outgoing administration and as the world found itself in an unprecedented global economic downturn, with the benefits of national space programs questioned more than ever before. There was no doubt that 50 years of the Space Age had altered humanity in numerous ways ranging from applications satellites to philosophical world views. Throughout its 50 years, NASA has been fortunate to have a strong sense of history and a robust, independent, and objective history program to document its achievements and analyze its activities. Among its flagship publications are Exploring the Unknown: Selected Documents in the History of the U.S. Civil Space Program, of which seven of eight projected volumes were completed at the time of the 50th anniversary. The reader can do no better than to turn to these volumes for an introduction to NASA history as seen through its primary documents. The list of NASA publications at the end of this volume is also a testimony to the tremendous amount of historical research that the NASA History Division has sponsored over the last 50 years, of which this is the latest volume.