Journal of the British Interplanetary Society VOLUME 72 NO.6 JUNE 2019 General interstellar issue THE MOTIVATION AND FREQUENCY OF INTERSTELLAR MIGRATIONS: A Possible Answer to Fermi’s Paradox Gregory L. Matloff TOWARDS A COMPREHENSIVE BIBLIOGRAPHY FOR SETI: Alan Reyes & Jason Wright ULTRAHIGH ACCELERATION NEUTRAL PARTICLE BEAM-DRIVEN SAILS James Benford & Alan Mole THE IMPLICATIONS OF NON-FASTER-THAN-LIGHT TYPE-3 KARDASHEV CIVILIZATIONS Agustín Besteiro HUMANITY’S FIRST EXPLICIT STEP IN REACHING ANOTHER STAR: The Interstellar Probe Mission Pontus Brandt et al. www.bis-space.com ISSN 0007-084X PUBLICATION DATE: 29 AUGUST 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. 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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.6 JUNE 2019 182 THE MOTIVATION AND FREQUENCY OF INTERSTELLAR MIGRATIONS: A Possible Answer to Fermi’s Paradox Gregory L. Matloff 186 TOWARDS A COMPREHENSIVE BIBLIOGRAPHY FOR SETI Alan Reyes & Jason Wright 190 ULTRAHIGH ACCELERATION NEUTRAL PARTICLE BEAM-DRIVEN SAILS James Benford & Alan Mole 198 THE IMPLICATIONS OF NON-FASTER-THAN-LIGHT TYPE-3 KARDASHEV CIVILIZATIONS Agustín Besteiro 202 HUMANITY’S FIRST EXPLICIT STEP IN REACHING ANOTHER STAR: The Interstellar Probe Mission Pontus Brandt et al. 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.6 June 2019 181 JBIS VOLUME 72 2019 PAGES 181–185 THE MOTIVATION AND FREQUENCY OF INTERSTELLAR MIGRATIONS: a Possible Answer to Fermi’s Paradox GREGORY L. MATLOFF Physics Dept., New York City College of Technology, CUNY, 300 Jay St., Brooklyn, NY 11211, USA Email [email protected] Human space exploration and exoplanet discoveries raise Fermi’s Paradox (“Where is Everybody?”) to new heights. The author suggests that technologically advanced interstellar civilizations might defer interstellar migration until their host stars enter the post-main-sequence ~108-year subgiant phase. Increased stellar luminosity will then enhance the performance of solar-photon-sail spacecraft. A scenario is presented for a 109-kg generation ship propelled by a graphene sail. The best destination for such a migration is a widely separated giant-dwarf binary. The giant would be used for deceleration; the vicinity of the dwarf would be colonized. At least one such system would likely closely approach the host star during its subgiant phase. Keywords: Fermi’s Paradox, Solar Sails, Stellar Evolution, Binary Stars, Interstellar Migrations 1 INTRODUCTION: WHERE IS EVERYBODY? [6]. Current radio-astronomy searches have been funded in an effort to resolve this paradox [7]. The Space Age is only seven decades old. In this short time, humans have lived in space for over one year, visited our Moon, Starting in the 1990’s, advanced observational techniques dispatched robotic probes to all major planets in our solar sys- have demonstrated the existence of thousands of planets with- tem and many smaller celestial objects and launched gravi- in the Milky Way Galaxy. Very recently, it has been shown that ty-assisted probes on slow voyages into our galaxy. Although Proxima Centauri, the nearest star to our Sun, is likely attended chemical rockets have propelled most of these ventures, some by a small planet orbiting in this red dwarf’s habitable zone [8]. craft have been propelled by solar-electric propulsion. Three Potentially habitable planets seem common in our galaxy. spacecraft to date have successfully tested the principle of pure photon propulsion by unfurling solar-photon sails. If current scientific speculation regarding the origin of life approximates reality, many of these planets support or have Experiments with beamed propulsion have been performed supported active biospheres. Intelligence may have evolved on and the construction and launch of wafer-thin interstellar some of these distant worlds. Some extraterrestrial societies probes propelled by the pressure of photons in microwave or may be technological. laser beams does not seem to be an unreasonable goal for the not-too distant future [1]. Yes, based upon humanity’s own sorry history, many devel- oping extraterrestrial civilizations might self-destruct through Self-sufficient space habitats constructed using lunar or as- nuclear war, pandemics, climate change, over-population, po- teroid material have been studied in depth [2,3]. It seems that litical turmoil, etc. But certainly, some among the millions or deep-space craft supporting hundreds or thousands of humans billions of habitable