DIRECT FUSION DRIVE for Interstellar Exploration S.A
Total Page：16
File Type：pdf, Size：1020Kb
Journal of the British Interplanetary Society VOLUME 72 NO.2 FEBRUARY 2019 General interstellar issue DIRECT FUSION DRIVE for Interstellar Exploration S.A. Cohen et al. INTERMEDIATE BEAMERS FOR STARSHOT: Probes to the Sun’s Inner Gravity Focus James Benford & Gregory Matloff REALITY, THE BREAKTHROUGH INITIATIVES and Prospects for Colonization of Space Edd Wheeler A GRAVITATIONAL WAVE TRANSMITTER A.A. Jackson and Gregory Benford CORRESPONDENCE www.bis-space.com ISSN 0007-084X PUBLICATION DATE: 29 APRIL 2019 Submitting papers International Advisory Board to JBIS JBIS welcomes the submission of technical Rachel Armstrong, Newcastle University, UK papers for publication dealing with technical Peter Bainum, Howard University, USA reviews, research, technology and engineering in astronautics and related fields. Stephen Baxter, Science & Science Fiction Writer, UK James Benford, Microwave Sciences, California, USA Text should be: James Biggs, The University of Strathclyde, UK ■ As concise as the content allows – typically 5,000 to 6,000 words. Shorter papers (Technical Notes) Anu Bowman, Foundation for Enterprise Development, California, USA will also be considered; longer papers will only Gerald Cleaver, Baylor University, USA be considered in exceptional circumstances – for Charles Cockell, University of Edinburgh, UK example, in the case of a major subject review. Ian A. Crawford, Birkbeck College London, UK ■ Source references should be inserted in the text in square brackets – [1] – and then listed at the Adam Crowl, Icarus Interstellar, Australia end of the paper. Eric W. Davis, Institute for Advanced Studies at Austin, USA ■ Illustration references should be cited in Kathryn Denning, York University, Toronto, Canada numerical order in the text; those not cited in the Martyn Fogg, Probability Research Group, UK text risk omission. Raghavan Gopalaswami, Aerospace Researcher, India ■ Captions must be labelled with their Fig. number and should be as short as possible. Lamartine Guimarães, Institute for Advanced Studies, Brazil Mark Hempsell, Hempsell Astronautics Ltd, UK Illustrations should be: Takuto Ishimatsu, Massachusetts Institute of Technology, USA ■ Colour or mono, but should be as close to print Les Johnson, Marshall Space Flight Center, USA resolution (300 dpi) as possible. Poor-quality illustrations may compromise the acceptance of Terry Kammash, University of Michigan, USA paper for publication. Images embedded in Word Kelvin F. Long, Initiative for Interstellar Studies documents may be acceptable, but JBIS reserves Inoue Makoto, Institute of Astronomy & Astrophysics Academia Sinica, Taiwan the right to request separate higher-resolution Gregory L. Matloff, City University New York, USA image files from the author prior to publication. Koichi Mori, Nagoya University, Japan ■ Responsibility for copyright clearance of images rests entirely with the author. Richard Obousy, Richard Obousy Consulting LLC, USA Robert Parkinson, BIS, Aylesbury, UK Submission of papers George Schmidt, NASA John H Glenn Research Center, Ohio, USA ■ Papers for consideration should be sent by Paul Schuch, The SETI League Inc, USA email to [email protected] as both a Word document and as a Word PDF file (in order to Tabitha Smith, Bifrost, USA check for font anomalies), together with any Andreas Tziolas, Variance Dynamical Corporation, USA separate image files. Chris Welch, The International Space University, Strasbourg, France ■ If a paper is accepted for publication, the Friedwardt Winterberg, University of Nevada, Reno, USA author will be asked to sign a License to Publish form. This can be downloaded at www.bis- space.com/wp-content/uploads/2012/08/ WebsiteLicense.pdf. ■ Authors will receive a complimentary copy of the issue in which their paper appears. Editor Roger Longstaff Deputy Editor Duncan Law-Green Associate Editors Stephen Ashworth, We respectfully ask authors to adhere to these Keith Cooper, Stephen Gamble, Paul Gilster, Rob Swinney, Production MP3 Media guidelines. Failure to do so will result in the Promotion Gill Norman JBIS Office British Interplanetary Society, Arthur C. Clarke House, delay of acceptable papers for publication. 27-29 South Lambeth Road, London, SW8 1SZ, United Kingdom tel +44 (0)20 7735 3160 email [email protected] www.bis-space.com Our full Guidelines for Authors can be downloaded DISTRIBUTION from www.bis-space.com JBIS is distributed worldwide by mail and may be received by annual subscription or purchase of single copies. It is available through membership of the British Interplanetary Society at much reduced rates. Subscription details for members, non-members and libraries are available from the above address. JBIS is a publication that promotes the mission of the British Interplanetary Society. Opinions expressed in signed articles are those of the contributors and do not necessarily reflect the views of the Editor or the Council of the British Interplanetary Society. Security clearance, where necessary, is the responsibility of the author. Published by the British Interplanetary Society. Registered Company No: 402498. Registered Charity No: 250556. Printed by Latimer Trend & Company Ltd, Estover Road, Plymouth, PL6 7PY, England. © 2019 British Interplanetary Society. No part of this magazine may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying or recording by any information storage or retrieval system without prior permission from the Publishers. CONTENTS VOLUME 72 NO.2 FEBRUARY 2019 38 DIRECT FUSION DRIVE for interstellar exploration S.A. Cohen et al. 51 INTERMEDIATE BEAMERS FOR STARSHOT: Probes to the Sun’s Inner Gravity Focus James Benford & Gregory Matloff 56 REALITY, THE BREAKTHROUGH INITIATIVES and Prospects for Colonization of Space Edd Wheeler 62 A GRAVITATIONAL WAVE TRANSMITTER A.A. Jackson and Gregory Benford 70 CORRESPONDENCE OUR MISSION STATEMENT The British Interplanetary Society promotes the exploration and use of space for the benefit of humanity, connecting people to create, educate and inspire, and advance knowledge in all aspects of astronautics. JBIS Vol 72 No.2 February 2019 37 JBIS VOLUME 72 2019 PAGES 37–50 DIRECT FUSION DRIVE for interstellar exploration S.A. COHEN1, C. SWANSON1, N. MCGREIVY1, A. RAJA3, E. EVANS1, P. JANDOVITZ1, M. KHODAK3, GARY PAJER2, T.D. ROGNLIEN4, STEPHANIE THOMAS2, MICHAEL PALUSZEK2 1Princeton Plasma Physics Laboratory, Princeton NJ, USA; 2Princeton Satellite Systems, Plainsboro, NJ, USA; 3Princeton University, Princeton, NJ, USA; 4Lawrence Livermore National Laboratory, Livermore, CA, USA. Email [email protected] (corresponding author) The Direct Fusion Drive rocket engine (DFD), based on the Princeton Plasma Physics Laboratory’s Princeton Field Reversed Configuration machine, has the potential to propel spacecraft to interstellar space and to nearby solar systems. This paper discusses a design for a starship that would be well suited to a variety of solar system and interstellar missions. DFD employs a unique plasma heating system to produce nuclear fusion engines in the range of 1 to 10 MW, ideal for human solar-system exploration, robotic solar-system missions, and interstellar missions. This paper gives an overview of the physics of the engine. Its innovative radiofrequency (RF) plasma heating system and the fuel choice are explained. The thrust augmentation method is described along with results of multi-fluid simulations that give an envelope of expected thrust and specific impulse. The power balance is described and the subsystems needed to support the fusion core are reviewed. The paper gives the latest results for the system design of the engine, including just-completed work done under a NASA NIAC study. A mass budget is presented for the subsystems. The paper then presents potential interstellar missions. The first are flyby missions. One is the proposed 550-AU mission that would use the Sun as a gravitational lens for exoplanet research. This mission can be done without a deceleration phase. Next, flyby missions – requiring major technological advances – to the nearest star are described. Finally we sketch a mission to orbit a planet in either the Alpha Centauri A or Alpha Centauri B systems. The mission analyses include a communications system link budget. DFD can operate in an electric-power-only mode, allowing a large fraction of the fusion power to be used for the payload and communications, enhancing the scientific return. All of the missions start in low Earth orbit. Keywords: Interstellar Mission, Solar Sail Spacecraft, Post-Newtonian Gravitational Theory 1 INTRODUCTION NOMENCLATURE The idea to use fusion power for spacecraft propulsion has a B = magnetic field long history [1, 2], with its support arising from the high ener- β = ratio of plasma pressure to magnetic-field energy density gy density of the fuel and the high velocity of the fusion prod- c = speed of light ucts. Early proponents of fusion rockets that provided steady – rather than pulsed or explosive – propulsion based their de- cs = ion sound speed signs on the fusion devices that were then in vogue, tokam- E = ratio of plasma FRC plasma core length to diameter aks [3, 4], mirror machines [5] and levitated dipoles [6]. The γLH = Lower-hybrid drift instability growth rate experimental results of that period in fusion history indicated Ip = plasma current that the plasma’s anomalous transport, meaning poor plasma energy confinement, and instability would necessitate low β, Isp = specific impulse D-T burning,