DOCSLIB.ORG

10. the Space Elevator

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
10. the Space Elevator 10. The Space elevator http://science.nasa.gov/headlines/y2000/ast07sep_1.htm [Pearson, Acta Astronautica 2 (1975) 785- 799] Probably the wildest nanotechnology idea in addition to self-replicating nanomachines is that of the space elevator. Contrary to self-replicating nanomachines, which we just concluded are to be considered science fiction for the foreseeable future, the space elevator concept is studied seriously and might according to several respected scientists become reality in a century or so. NASA has had a project to study it. Introduction to Nanoscience, 2005 JJ J I II × 1 So let us look a bit more into the concept. - It originated with the famous Russian scientist Konstantin Tsiolkovsky (known for pioneering rocketry ideas) who thought of a ”Celestial Castle” in geosynchronous Earth orbit attached to a tower on the ground. - Later a Leningrad engineer by the name of Yuri Artsutanov, wrote some of the first modern ideas Introduction to Nanoscience, 2005 JJ J I II × 2 about space elevators in 1960 in the Soviet newspaper Pravda. But this paper was the offifical newspaper of the communist party and thus was of course not read by anyone, so the idea did not gain wider recognition. - The popularization of the idea started, though, with the 1975 paper by Pearson, who not only did the basic strength calculation but also considered several complications and how it might be built [Pearson, Acta Astronautica 2 (1975) 785-799]. Inspired by this in 1978 Arthur C. Clarke popularized it to a wider audience in his 1978 science fiction novel, “Fountains of Paradise”. - If realized, it would allow for putting up a passenger with baggage to space for something like 200 USD - so it really would revolutionize space travel The elevator would consist of a tower (current idea is 50 km high) on top of which there is a cable. It would be linked to a counterweigth (e.g. an asteroid) above geostationary orbit, which is at about 36000 km high. The counterweight would due to centrifugal forces balance the whole structure. In principle it would also be possible to use the end part of the cable as a counterweight. Introduction to Nanoscience, 2005 JJ J I II × 3 The tower would for obvious reasons be at, or somewhere close, to the equator. The elevator itself would be on four to six ”elevator tracks” extending up the sides of the tower and cable, going to platforms at different levels. Electromagnetic vehicles (maglevs) traveling along the cable could serve as a mass transportation system for moving people, payloads, and power between Earth and space. 10.0.1. Space elevator cable material [Above, also http://www.isr.us/Downloads/niac_pdf/chapter2.html] For nanoscience the most interesting aspect is the cable material. The cable would have its maximum stress at geosynchronous orbit, due both to the counterweight but also due to its own mass Introduction to Nanoscience, 2005 JJ J I II × 4 - Bottom part of cable is pulled down by gravity, upper part pulled out by the counterweight (or strictly speaking of course not outwards but in the orbital direction, remember the classic 1-st year physics student nitpicking about centrifugal forces...) - Hence it must be the thickest at the geosynchronous orbit. - Thus one can for materials of known strength and density calculate how thick they need to be at the midpoint compared to at the bottom and top. The ratio between these diameters is called the taper factor. Introduction to Nanoscience, 2005 JJ J I II × 5 - For steel the taper factor is tens of thousands – clearly impossible. - For diamond, the taper factor is 21.9 including a safety factor, but diamond is brittle - What one would need is a very light material with a very high tensile strength - The attendees of this course will now of course realize carbon nanotubes are in principle perfect for this! - For nanotubes the taper factor might, depending on design, actually be less than 2. - Here is one proposed profile: Introduction to Nanoscience, 2005 JJ J I II × 6 (Note that in this design the cable is actually amazingly thin!) - The cable would probably be some sort of a composite: Introduction to Nanoscience, 2005 JJ J I II × 7 - It is also best to have one cross-sectional dimension much larger than the other to reduce the damage meteors can inflict on the cable. - The desired tensile strength for the space elevator is about 62 GPa. - Comparison with ch. 3b of this course shows that nanotubes can theoretically achieve up to maybe 300 GPa, and have experimentally already demonstrated to have 63 GPa. - But this is single nanotubes; one would still need to achieve the same in nanotube ropes. Introduction to Nanoscience, 2005 JJ J I II × 8 - Ropes can be made: [Xhang, Atkinson, Baughman, Science 306 (2004) 1359] but they have strengths which are “only” of the order of 1 GPa Still comparable to steel so even this is not so bad actually - There are two basic reason to this weakness: 1. That the single tubes are relatively short Introduction to Nanoscience, 2005 JJ J I II × 9 2. The weak van der Waals interaction between the tubes - Point 1 could be solved if it becomes possible to manufacture ropes from the recently made cm-long nanotubes efficiently - Point 2 might be solved by introducing covalent bonds between nanotubes: - By chemical means: Fukushima and Aida have very recently developed ways to make nanotube plastics 20-40 times stronger [article submitted, talk at NTNE 2005 conference] - By electron or ion irradiation: have increased nanotube bending moduli by 1-2 orders of magnitude (but this is not the same as the tensile strength, though) [Kis et al, Nature Materials 3 (2004)] Thus although no nanotube rope material strong enough for the space elevator yet exists, it is not impossible one might be manufactured within a very close future! 10.0.2. The other challenges [http://science.nasa.gov/headlines/y2000/ast07sep_1.htm] The NASA report also list 4 other challenges for building the thing: Introduction to Nanoscience, 2005 JJ J I II × 10 2. “Continuation of tether technology development to gain experience in the deployment and control of such long structures in space. ” 3. “The introduction of lightweight, composite structural materials to the general construction industry for the development of taller towers and buildings” - This is not so bad as it sounds: Buildings and towers can be constructed many kilometers high already today with existing technology 4. “The development of high-speed, electromagnetic [maglev] propulsion for mass-transportation systems, launch systems, launch assist systems and high-velocity launch rails. These are, basically, higher speed versions of the trams now used at airports to carry passengers between terminals. “ 5. “The development of transportation, utility and facility infrastructures to support space construction and industrial development from Earth out to GEO. The high cost of constructing a Introduction to Nanoscience, 2005 JJ J I II × 11 space elevator can only be justified by high usage, by both passengers and payload, tourists and space dwellers. “ There are also lots of possible erosion problems to be considered if the cable could be constructed, summarized in the following: • Lightning • Meteors • Space debris • Low-Earth-orbit • Wind • Atomic oxygen • Electromagnetic fields • Radiation • Erosion of cable by sulferic acid droplets in the upper atmosphere So obviously it is exactly yet wise to start investing money into a space elevator company: the challenges are huge and very likely there is some fatal flaw in the idea nobody has yet thought of! Introduction to Nanoscience, 2005 JJ J I II × 12 But comparing the wildest nanotech ideas, self-replicating fully human-designed machines and the space elevator, the latter one seems to be more realistic at least in the foreseeable future. And if the most optimistic visions of building a space elevator would be realized, then actually those of us who live longest might still see it in operation! Unless nanotech makes us all immortal and we all see it - haa haa Introduction to Nanoscience, 2005 JJ J I II × 13.
Load more

Recommended publications
  • Stairway to Heaven? Geographies of the Space Elevator in Science Fiction
    ISSN 2624-9081 • DOI 10.26034/roadsides-202000306 Stairway to Heaven? Geographies of the Space Elevator in Science Fiction Oliver Dunnett Outer space is often presented as a kind of universal global commons – a space for all humankind, against which the hopes and dreams of humanity have been projected. Yet, since the advent of spaceflight, it has become apparent that access to outer space has been limited, shaped and procured in certain ways. Geographical approaches to the study of outer space have started to interrogate the ways in which such inequalities have emerged and sustained themselves, across environmental, cultural and political registers. For example, recent studies have understood outer space as increasingly foreclosed by certain state and commercial actors (Beery 2012), have emphasised narratives of tropical difference in understanding geosynchronous equatorial satellite orbits (Dunnett 2019) and, more broadly, have conceptualised the Solar System as part of Earth’s environment (Degroot 2017). It is clear from this and related literature that various types of infrastructure have been a significant part of the uneven geographies of outer space, whether in terms of long-established spaceports (Redfield 2000), anticipatory infrastructures (Gorman 2009) or redundant space hardware orbiting Earth as debris (Klinger 2019). collection no. 003 • Infrastructure on/off Earth Roadsides Stairway to Heaven? 43 Having been the subject of speculation in both engineering and science-fictional discourses for many decades, the space elevator has more recently been promoted as a “revolutionary and efficient way to space for all humanity” (ISEC 2017). The concept involves a tether lowered from a position in geostationary orbit to a point on Earth’s equator, along which an elevator can ascend and arrive in orbit.
    [Show full text]
  • Stairway to Heaven? Geographies of Space Elevators in Science Fiction
    Stairway to Heaven? Geographies of Space Elevators in Science Fiction Dunnett, O. (2020). Stairway to Heaven? Geographies of Space Elevators in Science Fiction. Roadsides, 3, 42- 47. https://doi.org/10.26034/roadsides-202000306 Published in: Roadsides Document Version: Publisher's PDF, also known as Version of record Queen's University Belfast - Research Portal: Link to publication record in Queen's University Belfast Research Portal Publisher rights © 2020 The Authors. This is an open access article published under a Creative Commons Attribution-NonCommercial-ShareAlike License (https://creativecommons.org/licenses/by-nc-sa/4.0/), which permits use, distribution and reproduction for non-commercial purposes, provided the author and source are cited and new creations are licensed under the identical terms. General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made to ensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws. If you discover content in the Research Portal that you believe breaches copyright or violates any law, please contact [email protected]. Download date:29. Sep. 2021 ISSN 2624-9081 • DOI 10.26034/roadsides-202000306 Stairway to Heaven? Geographies of the Space Elevator in Science Fiction Oliver Dunnett Outer space is often presented as a kind of universal global commons – a space for all humankind, against which the hopes and dreams of humanity have been projected.
    [Show full text]
  • Today's Space Elevator
    International Space Elevator Consortium ISEC Position Paper # 2019-1 Today's Space Elevator Space Elevator Matures into the Galactic Harbour A Primer for Progress in Space Elevator Development Peter Swan, Ph.D. Michael Fitzgerald ii Today's Space Elevator Space Elevator Matures into the Galactic Harbour Peter Swan, Ph.D. Michael Fitzgerald Prepared for the International Space Elevator Consortium Chief Architect's Office Sept 2019 iii iv Today's Space Elevator Copyright © 2019 by: Peter Swan Michael Fitzgerald International Space Elevator Consortium All rights reserved, including the rights to reproduce this manuscript or portions thereof in any form. Published by Lulu.com [email protected] 978-0-359-93496-6 Cover Illustrations: Front – with permission of Galactic Harbour Association. Back – with permission of Michael Fitzgerald. Printed in the United States of America v vi Preface The Space Elevator is a Catalyst for Change! There was a moment in time that I realized the baton had changed hands - across three generations. I was talking within a small but enthusiastic group of attendees at the International Space Development Conference in June 2019. On that stage there was generation "co-inventor" Jerome Pearson, generation "advancing concept" Michael Fitzgerald and generation "excited students" James Torla and Souvik Mukherjee. The "moment" was more than an assembly of young and old. It was also a portrait of the stewards of the Space Elevator revolution -- from Inventor to Developer to Innovators. James was working a college research project on how to get to Mars in 77 days from the Apex Anchor and Souvik (16 years old) was representing his high school from India.
    [Show full text]
  • Review of New Concepts, Ideas and Innovations in Space Towers
    1 Review of New Concepts, Ideas and Innovations in Space Towers Mark Krinker Member of Advisory Board of Department of Electrical Engineering, City College of Technology, CUNY, New York, [email protected] Abstract Under Space Tower the author understands structures having height from 100 km to the geosynchronous orbit and supported by Earth’s surface. The classical Space Elevator is not included in space towers. That has three main identifiers which distingue from Space Tower: Space Elevator has part over Geosynchronous Orbit (GSO) and all installation supported only the Earth’s centrifugal force, immobile cable connected to Earth’s surface, no pressure on Earth’s surface. A lot of new concepts, ideas and innovation in space towers were offered, developed and researched in last years especially after 2000. For example: optimal solid space towers, inflatable space towers (include optimal space tower), circle and centrifugal space towers, kinetic space towers, electrostatic space towers, electromagnetic space towers, and so on. Given review shortly summarizes there researches and gives a brief description them, note some their main advantages, shortcomings, defects and limitations. --------------- Key words: Space tower, optimal space mast, inflatable space tower, kinetic space tower, electrostatic space tower, magnetic space tower. Introduction Brief History. The idea of building a tower high above the Earth into the heavens is very old [1]. The writings of Moses, about 1450 BC, in Genesis, Chapter 11, refer to an early civilization that in about 2100 BC tried to build a tower to heaven out of brick and tar. This construction was called the Tower of Babel, and was reported to be located in Babylon in ancient Mesopotamia.
    [Show full text]
  • Space Elevators: an Advanced Earth-Space Infrastructure for the New Millennium
    National Aeronautics and NASA/CP—2000–210429 Space Administration AD33 George C. Marshall Space Flight Center Marshall Space Flight Center, Alabama 35812 Space Elevators An Advanced Earth-Space Infrastructure for the New Millennium Compiled by D.V. Smitherman, Jr. Marshall Space Flight Center, Huntsville, Alabama This publication is based on the findings from the Advanced Space Infrastructure Workshop on Geostationary Orbiting Tether “Space Elevator” Concepts, NASA Marshall Space Flight Center, June 8–10, 1999. August 2000 The NASA STI Program Office…in Profile Since its founding, NASA has been dedicated to • CONFERENCE PUBLICATION. Collected the advancement of aeronautics and space papers from scientific and technical conferences, science. The NASA Scientific and Technical symposia, seminars, or other meetings sponsored Information (STI) Program Office plays a key or cosponsored by NASA. part in helping NASA maintain this important role. • SPECIAL PUBLICATION. Scientific, technical, or historical information from NASA programs, The NASA STI Program Office is operated by projects, and mission, often concerned with Langley Research Center, the lead center for subjects having substantial public interest. NASA’s scientific and technical information. The NASA STI Program Office provides access to the • TECHNICAL TRANSLATION. NASA STI Database, the largest collection of English-language translations of foreign scientific aeronautical and space science STI in the world. The and technical material pertinent to NASA’s Program Office is also NASA’s institutional mission. mechanism for disseminating the results of its research and development activities. These results Specialized services that complement the STI are published by NASA in the NASA STI Report Program Office’s diverse offerings include creating Series, which includes the following report types: custom thesauri, building customized databases, organizing and publishing research results…even • TECHNICAL PUBLICATION.
    [Show full text]
  • A Dynamic Study of an Earth Orbiting Tether Propulsion System
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 5-2007 A Dynamic Study of an Earth Orbiting Tether Propulsion System Stephen Edward Stasko University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Aerospace Engineering Commons Recommended Citation Stasko, Stephen Edward, "A Dynamic Study of an Earth Orbiting Tether Propulsion System. " PhD diss., University of Tennessee, 2007. https://trace.tennessee.edu/utk_graddiss/304 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Stephen Edward Stasko entitled "A Dynamic Study of an Earth Orbiting Tether Propulsion System." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Aerospace Engineering. Gary Flandro, Major Professor We have read this dissertation and recommend its acceptance: Joseph Majdalani, John Steinhoff, Kenneth Kimble Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a dissertation written by Stephen Edward Stasko entitled “A Dynamic Study of an Earth Orbiting Tether Propulsion System.” I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Aerospace Engineering.
    [Show full text]
  • An Investigation on the Economic Feasibility of Space Elevator Uzay
    An Investigation on The Economic Feasibility of Space Elevator Ayşe Meriç YAZICI 1 1 Ph.D. Student, İstanbul Aydın University Post Graduate Education Institute [email protected] Geliş Tarihi/Received: 21.04.2020 e-Yayım/e-Printed: 18.08.2020 ORCID ID: 0000-0001-6769-2599 ABSTRACT Although Space Elevator is a relatively new subject in the field of science concepts, it can now be considered as a science fiction. Space elevator was introduced as a concept in 1895 by Russian physicist Konstantin Tsiolkovsky. The space elevator has a great potential to be one of the appealing engineering projects ever designed. Nowadays, transporting the cargo to the space is both expensive, very complex and it also takes a long time. Construction of such a space elevator will enable humankind to make space travel and cargo transportation easier, cheaper. In this context, we mainly study how to extract the economic feasibility of this futuristic wonder of the giant mega structure for preliminary examination. In this study, a qualitative research method has been used in the scope of the relevant sources in the literature. The space elevator can significantly reduce costs in sending cargo to space and provide easier access to space. It may be beneficial in terms of space tourism in the following years. It can even be a stepping-stone for asteroid mining. The space elevator is under construction and can be an example and guide in removing economic feasibility or in future . The purpose of this article is to focus on the definition of space elevator and its construction, and also to argue on the reasons why the project is essential.
    [Show full text]
  • The Dynamics of Tethers and Space-Webs
    McKenzie, David J. (2010) The dynamics of tethers and space-webs. PhD thesis, University of Glasgow. http://theses.gla.ac.uk/1483/ Copyright and moral rights for this thesis are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Glasgow Theses Service http://theses.gla.ac.uk/ [email protected] Ph.D. Thesis: The Dynamics of Tethers and Space-webs David J. McKenzie, BEng Submitted in fulfilment of the requirements for the Degree of Doctor of Philosophy Departments of Mechanical and Aeronautical Engineering, Faculty of Engineering, University of Glasgow, G12 8QQ, Scotland, UK January 2010 ©David McKenzie, 2003-2010 Contents Abstract 15 Acknowledgements 16 1 Introduction 19 1.1 Overviewofthesis............................. 21 2 Literature review 23 2.1 Earlypioneers............................... 23 2.2 Tetherfundamentals ........................... 25 2.2.1 Fundamentaltetherconcepts . 26 2.2.2 Non-rotatingtethers . 26 2.2.3 Momentumexchange . 27 2.2.4 Motorizedmomentumexchangetethers . 29 2.2.5 Stagingwithmomentumexchange . 30 2.2.6 Deployingandrecoveryoftethers . 31 2.2.7 Captureandrendezvousoftethers . 33 2.2.8 WSBtrajectories ......................... 33 2.3 Tetherderivedstructures. 35 2 2.3.1 Deployedspacestructures . 35 2.3.2 Space-webs ............................ 36 3 Tether modelling 38 3.1 Constructingtheequationsofmotionofasystem .
    [Show full text]
  • History of the Tether Concept and Tether Missions: a Review
    Hindawi Publishing Corporation ISRN Astronomy and Astrophysics Volume 2013, Article ID 502973, 7 pages http://dx.doi.org/10.1155/2013/502973 Review Article History of the Tether Concept and Tether Missions: A Review Yi Chen,1,2 Rui Huang,3 Xianlin Ren,1 Liping He,1 and Ye He4 1 School of Mechanical, Electronic and Industrial Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China 2 School of Engineering and Built Environment, Glasgow Caledonian University, Glasgow G4 0BA, UK 3 School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China 4 The State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China Correspondence should be addressed to Yi Chen; [email protected] Received 13 December 2012; Accepted 16 January 2013 Academic Editors: S. Koutchmy and W. W. Zeilinger Copyright © 2013 Yi Chen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper introduces history of space tethers, including tether concepts and tether missions, and attempts to provide asource of references for historical understanding of space tethers. Several concepts of space tethers since the original concept has been conceived are listed in the literature, as well as a summary of interesting applications, and a research of space tethers is given. With the aim of implementing scientific experiments in aerospace, several space tether missions which have been delivered for aerospace application are introduced in the literature.
    [Show full text]
  • Sir Arthur Clarke and the Space Elevator
    Sir Arthur Clarke and the Space Elevator Jerome Pearson President, Star Technology and Research, Inc. [email protected] ISEC Space Elevator Conference Seattle, Washington 23-25 August 2013 1 Sir Arthur C. Clarke 16 Dec 1917-19 March 2008 Royal Air Force radio and comm, 1945 British Interplanetary Society, 1946 Science and science fiction writer Sri Lanka and diving business, 1956 Comsats and Clarke Orbit fame, 1963 Space elevator research, 1976-79 Space elevator novels, 1978, 1997 Knighted, 1998 “Sage of Science Fiction,” 2000 2 Clarke and My Teenage Inspirations The “big three” of science fiction: Asimov, Heinlein, Clarke (plus Bradbury) 3 3 Arthur Began it in 1945 1945 2013 Arthur Clarke, “Extra-terrestrial Relays,” Wireless World 1963 416 active satellites in Clarke Orbit Syncom 2 4 Arthur Inspired Me on the Orbital Tower 1969 description of GEOSats on “imaginary towers” 1975, “The Orbital Tower” in Acta Astronautica 1976, Arthur begins our correspondence 1978, “The Fountains of Paradise” The Orbital Tower Arthur in 1964 5 The U.S. Bicentennial IAC, 1976 Great conference, and my first presentation on the Orbital Tower Met Robert Forward, Georg von Tiesenhausen (who suggested looking at the lunar space elevator, since the Earth elevator was so hard) Received Arthur’s letter, article, and questions on the space elevator 6 Clarke’s First Letter to Me, 1976 His paper addressed the collision problem He expected 104-106 objects Space Command now tracking 21,000 He wondered how to propel high-speed climbers Suggested
    [Show full text]
  • Teresa J. Stuchi, IF-UFRJ
    Teresa J. Stuchi, IF-UFRJ IF-Junho/2015 Space elevators 1. Torre de Babel (Moises, Genesis (11:1-9) 2. Escada de Jacob (Genesis (28:12)) Space elevators 3. K.E.Tsiolkovski Speculation about Earth and Sky and on Vesta (1895) 4. Yuri Artsutanov (1960) Komosomolskaya Pravda 5. Arthur C. Clarke The fountains of Paradise (tower in Sri Lanka) Yuri Artsutanov and Jerome Pearson 35.800 km K.E.Tsiolkovski 35.800 km, GEO: órbita geoestacionária AS THE CAR CLIMBS, THE ELEVATOR TAKES ON A 1 DEGREE LEAN, DUE TO THE TOP OF THE ELEVATOR TRAVELING FASTER THAN THE BOTTOM AROUND THE EARTH (CORIOLIS FORCE). THIS DIAGRAM IS NOT TO SCALE. 35.800 km VARIAÇÃO DA VELOCIDADE COM A ALTITUDE The velocity at the top of the tower is so great (10.93 km/s) that a payload released from there would escape the Earth without rocket propulsion. The Space Elevator will succeed 50 years after everyone has stopped laughing. -Arthur C. Clarke NANO TUBOS DERAM VIDA NOVA AO SONHO DA BABEL Lagrangian Points Earth‐Moon L4 64,000 km 58,000 km L2 L 1 380,000 km L3 L5 LUNAR SPACE ELEVATOR There are two lunar-synchronous points where an elevator could be placed that would be stable: the libration points L1 and L2 Anchored Lunar Satellites Compared to the Anchored Earth Satellite ( Jerome Pearson) What are tethered satellites? Space missions TSS 1992 NASA TSS-1R 1996 NASA TIPS 1996 US Navy YES2 2007 ESA MAST 2007 JAXA Artistic representation (NASA) YES2 (2007) - ESA TSS-1 (1992) - NASA Tether mudando a órbita de satélite Momentum-exchange tethers (nonconductive tethers representing passive propulsion).
    [Show full text]
  • The Physics of the Space Elevator by P. K. Aravind
    The physics of the space elevator P. K. Aravind Department of Physics, Worcester Polytechnic Institute, Worcester, Massachusetts 01609 ͑Received 1 May 2006; accepted 10 November 2006͒ A space elevator is a tall tower rising from a point on the Earth’s equator to a height well above a geostationary orbit, where it terminates in a counterweight. Although the concept is more than a century old, it was only with the discovery of carbon nanotubes that it began to receive serious scientific attention. NASA commissioned a study of the space elevator in the late 1990s that examined the feasibility of such a structure and explored many of its applications. I explain the basic mechanical principles underlying the construction of a space elevator and discuss several of its applications: the transport of payload into space and the launching of spacecraft on voyages to other planets. © 2007 American Association of Physics Teachers. ͓DOI: 10.1119/1.2404957͔ I. INTRODUCTION its structure showed that no known material was strong enough to build it. A space elevator is a tall tower rising from a point on the This pessimism was largely neutralized by the discovery 7 Earth’s equator to a height well above a geostationary orbit, of carbon nanotubes in 1991. Carbon nanotubes, which are where it terminates in a counterweight ͓see Fig. 1͑a͔͒. Al- essentially rolled up sheets of graphite, have a tensile though the idea of such a structure is quite old, it is only strength greatly exceeding that of any other known material. within the last decade or so that it has attracted serious sci- Their high tensile strength, combined with their relatively entific attention.
    [Show full text]