Deep Space Propulsion

K.F. Long

Deep Space Propulsion

A Roadmap to Interstellar Flight

K.F. Long Bsc, Msc, CPhysVice President (Europe), Icarus InterstellarFellow British Interplanetary SocietyBerkshire, UK

ISBN 978-1-4614-0606-8 e-ISBN 978-1-4614-0607-5DOI 10.1007/978-1-4614-0607-5Springer New York Dordrecht Heidelberg London

Library of Congress Control Number: 2011937235

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This book is dedicated to three people whohave had the biggest influence on my life.My wife Gemma Long for your continuedlove and companionship; my mentorJonathan Brooks for your guidance andwisdom; my hero Sir Arthur C. Clarkefor your inspirational vision – for Rama,2001, and the books you leave behind.

Foreword

We live in a time of troubles. It is easy to name a few of them: endless wars,

clashes of cultures, nuclear proliferation, overpopulation, global climate warming,

economic recession, political disarray. It is also easy to give up and conclude that

all is hopeless for our civilization and possibly for all humanity.

However, is such pessimism truly warranted? The year 2010 witnessed the first

reasonably solid detection of potentially habitable worlds circling nearby stars. Our

understanding of the variety of life forms that could inhabit these worlds has also

been broadened.

Perhaps more significantly, another milestone of 2010 was the first successful

flight test of a non-rocket propulsion system that could someday evolve into a star

drive. True – the solar sails that may evolve from the successful interplanetary test

flight of the Japanese Ikaros probe will never achieve the performance of StarTrek’s mythical Enterprise – but they represent a start.

Progress towards controlled thermonuclear fusion continues. And at the CERN

laboratory on the Italian-Swiss border, the Large Hadron Collider is now opera-

tional. It is not impossible that advances in our understanding of particle physics

prompted by experiments at this new facility will ultimately lead to our taming of

the antimatter/matter annihilation. Maybe some theoretical breakthrough will actu-

ally lead to a warp drive or a means of tapping the enormous energies of the

universal vacuum.

It is impossible to know which of these new technologies – sails, fusion, or

antimatter – will lead to the first human probes and ships capable of crossing the

interstellar gulfs. But if you are interested in participating in the adventure of

expanding the terrestrial biosphere into new realms, this book is an excellent

place to hone your skills.

The author is a major contributor to the British Interplanetary Society Project

Icarus, which is investigating near-term techniques that might lead to probes

capable of reaching our Sun’s nearest stellar neighbors. As well as reviewing the

current state of interstellar propulsion technologies, Kelvin Long provides an

extensive bibliography that will be an invaluable aid to the novice researcher.

vii

Chapter exercises are also included so that young engineers and physicists can

practice their skills.

Historical discussions regarding the evolution of flight within and outside

Earth’s atmosphere will be of great interest to the casual reader. References to

science fiction demonstrate the significance of literature in inspiring much of the

scientific inquiry that has led us to the threshold of galactic citizenship. And the

color plates present the beautiful work of space artists and illustrators.

Only a few humans have felt the crunch of lunar soils beneath their booted feet.

A somewhat larger number have remotely controlled their roving vehicles as they

cross the deserts of Mars or communicated with Voyager probes now on the fringe

of galactic space. In all likelihood, only a few will control our interstellar robots and

fewer still will ride the galactic high road to our next stellar homes. But this book

allows many to contribute to and share in the adventure.

Just maybe today’s interstellar pioneers will help stem the tide of pessimism.

Perhaps, just perhaps, books like this may help develop a welcome sense of

optimism and feeling of hope among the readers.

New York City College of Technology, CUNY Dr. Greg Matloff

viii Foreword

Preface

Two lights for guidance. The first, our little glowing atom ofcommunity, with all that it signifies. The second, the cold lightof the stars, symbol of hypercosmical reality, with its crystalecstasy. Strange that in this light, in which even the dearest loveis frostily assessed, and even possible defeat of our half-wakingworld is contemplated without remission of praise, the humancrisis does not lose but gains significance. Strange, that it seemsmore, not less, urgent to play some part in this struggle, thisbrief effort of animalcules striving to win for their race someincrease of lucidity before the ultimate darkness.

Olaf Stapledon

This book is about robotic exploration of the nearby stars and the prospects for

achieving this within the next century. In particular, we will focus on the propulsion

technology that will be used to accomplish such an ambitious objective. This is

so called ‘game changing’ technology that goes beyond conventional chemical

rockets, using exotic fuels and more efficient engines for the purpose of an

interstellar mission. This includes ideas for engines based upon harnessing the

emitted energy of the Sun, using fusion reactions or even tapping the energy release

from matter-antimatter annihilation reactions. This book serves as an essential

primer for anyone new to this field who wishes to become familiar with the ideas

that have already been developed and how to attain the necessary theoretical tools

to create similar ideas for themselves. If, by the end of this book, you are thinking of

your own ideas for how machines can be propelled across the vastness of space,

then this book will have been successful in its ultimate aim.

At the dawn of this new millennium we can look back on the previous century

with pride, knowing that humanity took its first steps into space and even walked

upon the surface of the Moon. We have collected a wealth of data on the many

planets and moons of our Solar System, and our robotic ambassadors are still

pioneering the way so that one day humans may hope to follow where they lead.

The Moon and Mars are the current focus of human ambitions in space, and this is

ix

right for the short-term goals of our species. But in the long term, missions to places

much further away will become not just aspirations but vital to our survival.

From the outset of this text, we must be truthful and admit that the technology

to enable human transport to other stars is currently immature. The physics, engi-

neering and physiological requirements are unlike anything we have ever encoun-

tered, and this unique problem demands our full attention if we are to ever cross the

enormous gulfs of space that separate the stars in our galaxy and become a truly

spacefaring civilization. But if we are bold and eventually attempt this, the scien-

tific, economic and spiritual rewards will be many, and our civilization will become

enriched for the attempt. Until then, we must be content with robotic exploration

and to push that technology to its limit. We must continue to launch missions to

the outer planets of our Solar System to explore those cold but interesting worlds.

Eventually, our robotic probes will break through the termination shock of the

solar heliosphere and pass out into the Kuiper Belt to explore many strange new

dwarf planets, some perhaps yet undiscovered. Then they will be sent to much

further distances out into the Oort Cloud to investigate the myriad of comets that

orbit our Solar System in large period trajectories. Finally those same robots will

enter the outer reaches of the interstellar medium, the diffuse nebula of space that is

dispersed between the stars, and for the first time in history a human made machine

would have fully left the gravitational cradle of our Sun.

By this time, the technology performance of our machines should have improved

by many orders of magnitude so that missions to the nearest stars will become

possible and scientific data return will become common. What will those probes

discover? Perhaps unusual planets with oceans made of materials thought impossi-

ble where life might be swimming among its depths. The astronomical knowledge

gained will be highly valuable; the chance to be so close to another star and its

orbiting worlds will enrich our knowledge of the universe and give us a better

understanding of its structure, evolution and origin.

A few moments spent thinking about the interstellar transport problem quickly

leads to the realization that there are two main extremes to reaching the stars. We

can build very lightweight vehicles with a limited payload size in the hope that their

small mass allows for large speeds, such as a solar sail. Alternatively, we can build

massive vehicles the size of small moons, which will move slowly and take perhaps

thousands of years to reach their destination; these are so called world ships. For

any form of human exodus to another world, clearly the latter option is the only

credible approach. However, as one digs into the interstellar literature we find that

there are approaches to this problem that lay between these two extremes. We find

that physicists have invented clever theoretical (and some practical) means of

allowing a large mass scientific payload to be delivered to a destination at a

speed of a few to tens of percent of light speed, thus getting to the target within

decades. It is then just a matter of the engineering technology progressing to an

acceptable readiness level. Many of these schemes are discussed in this book.

In reading this book it will be clear that the author favors the nuclear pulse

propulsion approach for interstellar missions. This is along the lines of the historical

Orion and Daedalus concepts. It should be noted that this is not because of a belief

x Preface

that other concepts do not meet the requirements for interstellar missions. In fact the

opposite is true, and technology such as solar sails, laser sails and microwave sails

in particular do offer great potential for near term demonstration. However, it is a

personal belief that nuclear pulse technology is nearly ready for use now, if not

already available in some form, and is the most appropriate route for an interstellar

flight. Power is what will take us to the stars, and sending something there fast

requires powerful engines as provided by the nuclear pulse options. In the end, it

is likely that the first interstellar probe will be a combination of propulsion

technologies – a hybrid design utilizing nuclear electric, sails and nuclear pulse to

augment different parts of the mission. When this happens, all of the individual

efforts over the decades of research that have gone into making each of these

technologies ready will have been worth the effort.

Another personal view that has been taken by this author is that Mars should be

the next destination for human exploration. This will push our technology forward

while also beginning the establishment of a human colony on another world.

Contrary to some claims, the exploration of Mars is not prohibitively expensive if

done in a manner similar to the proposed Mars Direct plan. National and interna-

tional space agencies need a common focus and a common goal – Mars is the

logical candidate and a clear springboard upon which a full program of interstellar

exploration may begin. Indeed, there are no technological reasons preventing us

from starting direct colonization of Mars today.

Many people believe that interstellar travel, even robotic exploration, is so

difficult and the obstacles so unsurpassable that it will be many millennia before

we can attempt it. However, it is the hope of this book to demonstrate to the reader

that not only is interstellar travel perfectly possible, it is within our grasp, and the

first unmanned mission will likely be launched by the end of the twenty-first

century (a bold prediction) and certainly by the mid twenty-second century.

As will be shown, many feasibility design studies have already been undertaken

historically, often involving teams of physicists and engineers, producing study

reports that demonstrate the engineering problems and potential solutions. These

people are among a growing network of optimists that share in a single vision that

the human destiny in space lies not just with the Moon and nearby planets, but much

further to other worlds around other stars. History will show which one of these

concepts becomes the true template for how our robotic ambassadors first enter the

orbit of another star and achieve this seemingly impossible and long desired

ambition.

Berkshire, UK K.F. Long

Preface xi

Acknowledgments

There are many people I would like to thank in preparing the manuscript for this

book. Firstly, a big thank you to my wife Gemma Long for the patience you have

shown during the hours I was working on this book. Many other members of my

family also had to put up with long periods of absence during this busy writing

period. I would especially like to thank my parents Susan Kelly, Kevin Long,

Maureen Perrin and Michael Perrin. For reviewing parts of the manuscript

and giving constructive comments on earlier drafts I would like to thank Paul

Gilster, Greg Matloff, Marc Millis, Richard Obousy, Adam Crowl, Pat Galea,

Paul Thompson, Gemma Long and Jonathan Brooks. Any errors are solely this

author’s responsibility. A special thanks to Greg Matloff for writing the foreword

and supporting me in this project. Discussions with many other people over the last

2 years have helped me to understand what a difficult and wide scoping academic

subject interstellar research is. Other than those already mentioned above, I would

also like to thank the following for constructive discussions or for helping me in

some capacity during this work, including Claudio Maconne, Bob Parkinson,

Martyn Fogg, Jim French, Alan Bond, Gerry Webb, Penny Wright, Friedwardt

Winterberg, Richard Osborne, Andreas Tziolas, Jim Benford, Rob Swinney,

Robert Freeland, Andy Presby, Andreas Hein, Philip Reiss, Ian Crawford, Stephen

Baxter, Stephen Ashworth, Gerald Nordley, Giovanni Vulpetti, Claudio Bruno,

Tibor Pacher, Rich Sternbach, David Johnson, Eric Davies, Ralph McNutt, George

Schmidt, Claudio Bruno, Giovanni Vulpetti, Charles Orth, Dana Andrews, John

Hunt, Remo Garattini, Mike McCulloch, Stephen Ashworth. Many discussions with

the ever insightful Adam Crowl have especially been educational in helping me to

learn this subject, with humility. Several people mentioned above are associated

with the Project Icarus Study Group – we are pioneers together. In the course of my

research, I would like to pay tribute to the evolving source that is the internet and

the superb ‘Atomic Rockets’ web site run by Winchell Chung Jr. I must also

mention the staff at the British Interplanetary Society, particularly the Executive

Secretary Suszann Parry as well as Mary Todd, Ben Jones, Mark Stewart (BIS

Honorary Librarian), Chris Toomer (JBIS Editor), Clive Simpson (Spaceflight

xiii

Editor), for their continued efforts in promoting space exploration and providing

excellent publications which I relied upon for information. For supplying graphics

I would like to thank David Hardy, Adrian Mann, Alexandre Szames and Christian

Darkin. Jack Weedon and Peter Johnson are thanked for their long time encourage-

ment and support. Acknowledgement is also given to the NASA images library for

kindly allowing free use of their wonderful pictures for public use. I would like to

thank my editor at Springer Maury Solomon for being patient with the manuscript

delivery and publishing agent John Watson who introduced me to the team.

In the review of propulsion concepts I have been selective in what projects to

discuss. If I have left out some important schemes or research it is not because I

don’t think they are relevant but either due to page/time limitations or simply

because I did not know of the existence of such methods. Finally, my thanks go

to Sir Arthur C Clarke with whom I had the honor of meeting just the once. His

literature in both science fiction and science writing has changed my view of the

world and the possibilities for the future of our species in the exploration of space.

My own vision is his inheritance and an inspiration for the generations ahead.

xiv Acknowledgments

Contents

1 Reaching for the Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 An Overview of Propulsion Schemes for Space . . . . . . . . . . . . . . . . . . . 1

1.3 Practice Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2 The Dream of Flight and the Vision of Tomorrow . . . . . . . . . . . . . . . . . . . . 11

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.2 Becoming a Spacefaring Civilization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.3 The Promise of the Future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.4 Why We Shouldn’t Go Out into Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.5 Why We Should Go Out into Space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3 Fundamental Limitations to Achieving Interstellar Flight. . . . . . . . . . . . 27

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3.2 How Much Speed Is Required to Reach the Stars? . . . . . . . . . . . . . . . . 27

3.3 How Much Energy Is Required to Reach the Stars? . . . . . . . . . . . . . . . 35


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

4 Aviation: The Pursuit of Speed, Distance, Altitude, and Height. . . . . . 39

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.2 The History of Propulsion in Aviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

4.3 The Physics of Aviation Propulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

5 Astronautics: The Development and Science of Rockets . . . . . . . . . . . . . . 49

5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

5.2 The History of Propulsion in Rocketry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

xv

5.3 The Physics of Rocket Propulsion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

5.4 Rockets for Space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

5.5 Practice Exercises. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

6 Exploring the Solar System and Beyond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

6.2 Near Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.3 The Colonization of Mars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

6.4 Other Planetary Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

6.5 Mining He-3 from the Gas Giants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

6.6 The Outer Solar System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

7 Exploring Other Star Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

7.2 The Stars and the Worlds Beyond. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

7.3 The Discovery and Evolution of Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

8 Solar System Explorers: Historical Spacecraft . . . . . . . . . . . . . . . . . . . . . . . 117

8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

8.2 Precursor Mission Probes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

8.3 Pioneer Probes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

8.4 Voyager Probes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

8.5 Galileo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

8.6 Ulysses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

8.7 Cassini-Huygens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

8.8 Deep Space 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

8.9 Cosmos I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

8.10 New Horizons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

8.11 Dawn. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

8.12 Interstellar Boundary Explorer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

8.13 Summary Discussion on Probe Design. . . . . . . . . . . . . . . . . . . . . . . . . . . 132


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

9 Electric and Nuclear-Based Propulsion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

9.2 Electric Propulsion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

9.3 Nuclear Thermal and Nuclear Electric Propulsion. . . . . . . . . . . . . . . 144

9.4 The Interstellar Precursor Probe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

9.5 The Thousand Astronomical Unit Mission. . . . . . . . . . . . . . . . . . . . . . . 147

xvi Contents

9.6 The Innovative Interstellar Explorer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

9.7 Project Prometheus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

9.8 Practice Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

10 Sails & Beams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

10.2 Solar Sailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

10.3 The Interstellar Heliopause Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

10.4 Interstellar Probe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

10.5 Beamed Propulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

10.6 Beamed Microwaves and Starwisp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

10.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

11 Nuclear Fusion Propulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

11.2 Fusion: The Holy Grail of Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

11.3 Fusion Power for Space Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

11.4 The Enzmann Starship. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

11.5 Project Daedalus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

11.6 Project Longshot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

11.7 Project VISTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201

11.8 Discovery II. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

11.9 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

12 External Nuclear Pulse Propulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207

12.2 Nuclear Pulse Detonation and Project Orion. . . . . . . . . . . . . . . . . . . . . 207

12.3 The Medusa Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

12.4 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

13 Towards Relativistic Propulsion: Antimatter

and the Interstellar Ramjet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

13.2 Relativity in Space Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220

13.3 The Interstellar Ramjet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

13.4 The Bussard Ramjet Spacecraft Concept . . . . . . . . . . . . . . . . . . . . . . . . 226

13.5 Matter-Antimatter Annihilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

13.6 The AIMStar Spacecraft Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229

13.7 The ICAN-II Spacecraft Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233

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14 Aerospace Design Principles in Interstellar Flight . . . . . . . . . . . . . . . . . . . 235

14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

14.2 Principles of Aerospace Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

14.3 Systems Engineering Approach to Concept Design Studies . . . . . 238

14.4 Technology Readiness Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243

14.5 A Concept Design Problem for a Precursor Mission Proposal . . 244

14.5.1 Scoping Concept Design Space . . . . . . . . . . . . . . . . . . . . . . . . . 245

14.5.2 Concept Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

14.6 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

15 The Scientific, Cultural and Economic Costs

of Interstellar Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263

15.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263

15.2 The Advance of Science. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263

15.2.1 Planetary Physics, Including Terrestrial

and Giant Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265

15.2.2 Stellar Physics, Including Different Spectral Types . . . . 265

15.2.3 The Presence and Evolution of Life. . . . . . . . . . . . . . . . . . . . . 265

15.2.4 The Physics of the Interstellar Medium . . . . . . . . . . . . . . . . . 266

15.2.5 The Physics of the Kuiper Belt and Oort Cloud

Layers of Different Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

15.2.6 Galactic Structure, Cosmology

and the Global Picture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

15.2.7 Exotic Physics, Including Gravitational Issues . . . . . . . . . 267

15.2.8 Engineering Design Issues Such as Spacecraft

Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

15.3 Cultural Growth and the Rise and Fall of Civilization . . . . . . . . . . 271

15.4 The Economics of Space Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

16 The Role of Speculative Science in Driving Technology . . . . . . . . . . . . . 287

16.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

16.2 The Connection between Science and Fiction . . . . . . . . . . . . . . . . . . . 288

16.3 Breakthrough Propulsion Physics and the Frontiers

of Knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291

16.4 NASA Horizon Mission Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . 300

16.5 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

17 Realising the Technological Future and the Roadmap

to the Stars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

17.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

17.2 International Co-operation in the Pursuit of Space . . . . . . . . . . . . . . 306

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17.3 Establishing Precursor Missions and the Technological

Roadmap for Interstellar Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

17.4 Project Icarus, Son of Daedalus, Flying Closer

to another Star . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312

17.5 The Alpha Centauri Prize. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318

17.6 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323

18 From Imagination to Reality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325

Epilogue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345

Appendix A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

Appendix B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351

Appendix C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

Appendix D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361

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About the Author

K.F. Long was born in Cambridge, England. He holds a Bachelors degree in

Aerospace Engineering and a Masters degree in Astrophysics, both from Queen

Mary College University of London. He has been a college and university teacher

and served for several years in the Parachute Regiment Volunteer Reserve of the

British Army. He currently works as a physicist in industry. He has published

numerous papers and articles on the subject of astrophysics and space exploration

and is currently the Assistant Editor of the Journal of the British InterplanetarySociety. He has also contributed to many other publications on interstellar travel.

He has appeared on the Austrian Broadcasting Radio Station FM4, as well as in thedocumentary How To Colonize the Stars produced by Christian Darkin. He is a

Fellow of the Royal Astronomical Society, a chartered member of the Institute of

Physics, a member of The Planetary Society, a member of the American Institute

of Aeronautics & Astronautics, Fellow of the British Interplanetary Society, and an

associate member of the International Association for Astronomical Artists. He is a

Practitioner of the Tau Zero Foundation, which actively promotes and coordinates

international research into interstellar flight and within this capacity was the

co-founder of an interstellar research initiative called Project Icarus. He is also

the Vice President (Europe) and co-founder of the non-profit Icarus Interstellar.

He is happily married to Gemma and likes to spend his spare time reading and writing

science fiction, spacecraft model building and using his Schmidt-Cassegrain

telescope.

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Deep Space Propulsion

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