RINCIPIUM PThe Newsletter of the Institute for Interstellar Studies ™

Letter from the Director

News from the Institute

‘Advances’

Cubesats

Retrospective: Daedalus

Book Reviews R IN O T F E R E S T

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S ™ TUDIES Scientia ad sidera www.I4IS.org Knowledge to the Stars A letter from Kelvin F. Long

Dear friends, I am proud to have been the originator of this organisation and I am deeply We live in exciting times. In recent years honoured that many others have shared in many planets have been detected orbiting that vision and are actively assisting with around other stars. This is helping us to its foundation. My colleagues and I will realise that there are places to go, as work to make the Institute a success in the predicted in the many works of science coming years. This excellent newsletter fiction over the last century. In addition, represents our first publications outreach we are now witnessing the emergence of activity, other than the Institute blog the commercial space sector and space page. In time we hope this newsletter will tourism. This gives us hope and optimism serve as an exciting information source for that despite the challenges we face down the community. I want to personally thank here on Earth, better times lay ahead for Keith Cooper for taking on this role of our space-aspiring society. A key Editor and Adrian Mann for assisting with component of this is learning how to work the editorial graphics and production. I together in a spirit of co-operation and hope you enjoy this first issue of friendship and this is precisely what Principium and keep an eye on the interstellar societies tend to encourage. Institute’s website as we gradually With optimism, hope and an inspirational announce more activities in the coming vision, we can reach those distant stars. months. Scientia ad sidera. The oldest interstellar society today is the London-based British Interplanetary Society (BIS), founded in 1933 and fast Kelvin F. Long approaching its 80th anniversary. Executive Director Although it examines the broad issues The Institute for Interstellar Studies™ associated with robotic and human spaceflight, interstellar has always been a core component of its work, with studies like Project Daedalus in the 1970s and the famous ‘red cover’ issues of the Journal of the BIS that were published between 1974 and 1991. These considered subjects such as the design of World Ships, interstellar precursor missions and the prospect for intelligent life in the Universe. The BIS has been the torch-holder for the interstellar vision for many decades. In the last few years many others have decided to address the interstellar problem, by the formation of organisations or societies. This includes Vision 21, PI Club, the Interstellar Propulsion Society, the Tau Zero Foundation, Icarus Interstellar and 100 Year Starship. The latest entry into this group is the Institute for Interstellar Studies™. Our main focus is the nurturing of people through our educational academy and the fostering of starship- related research and development.

Principium | Issue 1 | December 2012 Page 2 News from the Institute

I4IS blasts off! The first four students to have signed Creating an interplanetary up to the projects are investigating topics The Institute for Interstellar Studies ™ as varied as designing interstellar probes; civilisation (I4IS) was launched on 14 September learning how to decelerate an interstellar I4IS team-member Stephen Ashworth has 2012. Founded in the United Kingdom, probe from a tenth of the speed of light as detailed his path for society to become an it ultimately aims to have a global it approaches its destination star; and interstellar civilisation. Inspired by a outreach. Executive Director Kelvin exploring agricultural techniques for a posting on the Centauri Dreams website, Long says, “I am very excited about this deep space microgravity environment, he describes on his blog a “creative opportunity, for which the time has now perhaps in a space station or a worldship, community of public and private come. Many have worked towards the populated by a thousand people. fulfillment of an interstellar vision over institutions acting in concert... and a set the past decades, and it is hoped that the of new technologies which both multiply institute will pull the community wealth and introduce new problems.” together behind a common purpose and On the road to the stars From thereon he describes a 14-point a bold enterprise.” The I4IS held its inaugural planning and scenario, starting with government progress meeting in the fitting setting of exploration of low-Earth orbit and the Learn more in Kelvin’s introduction to the British Library in London on 29 foundation of outposts there (already this issue on page 2. September 2012. Discussing everything achieved) followed by the onset of space from the Institute’s priorities during the tourism and private space enterprises that coming years to Institute-led projects and we are seeing today, leading to solar power Spaced-up revenue generation, the conversations satellites to energise the burgeoning interplanetary civilisation that could Dr Chris Welch, the deputy chair for I4IS’ during the workshop were abuzz with embark on new Moon missions and a Senior Advisory Council, gave a great ideas and a tremendous amount of lunar colony by 2050, Mars and Venus by presentation about the Institute to the hope for the future. 2080 and bonafide colonies on or in orbit SpaceUp ‘unconference’ (where I4IS members present included Kelvin around numerous planets by the participants decide the agenda) in Long, Rob Swinney, Jeremy Clark, beginning of the 22nd century. By the Stuttgart in September. Introducing the Jonathan Brooks, Richard Osborne, beginning of the 23rd century the Institute for the packed audience, he Stephen Ashworth and Keith Cooper. interplanetary economy could have grown described I4IS as “a nexus for the Look out for some of the things the by ten billion compared to today’s activities related to the challenges of Institute has planned coming over the economy, writes Ashworth, with asteroid achieving robotic and human interstellar next twelve months – the road to the stars mining in particular contributing to it and flight.” He recounted the British starts here! most of our descendants living in space. Interplanetary Society’s Daedalus project (see elsewhere this issue) and how I4IS Do you agree with Stephen Ashworth's plans to build on that work by seeking to roadmap? write to us and tell us your conduct credible research into the science visions of the future. and technology of starships, ultimately progressing towards a capable and confident human species in interplanetary space, with benefits for life back home too. Welch also gave special mention to the prospect of the I4IS Academy (directed by Rob Swinney), which will see I4IS members, with Executive Director students takes MSc projects with the Kelvin Long on the left, discuss Institute through the International Space interstellar matters at the British Library. University near Strasbourg.

To keep up to date with the latest I4IS news, check out the Starship Log on the Institute’s Interstellar Index http://www.interstellarindex.com/ blog / or follow the Institute on Facebook http://www.facebook.com/InterstellarInstitute Dr Chris Welch introduces the Institute for Interstellar Studies at the SpaceUp and LinkedIn ‘unconference’ in September. http://www.linkedin.com/groups?home &gid=4640147&trk=anet_ug_h m

Principium | Issue 1 | December 2012 Page 3 ADVANCES Ahead Warp Factor One!

Could we warp space to our the Universe. There was only one space-time flat. The bubble, however, drawback: you would have to convert every causes space in front of the craft to will, reducing interstellar travel atom in the visible Universe into pure contract, in essence pulling the target energy to obtain the required power. destination towards it. Behind the vessel times to just weeks rather the bubble allows space-time to relax and than years? It seems Less energy to warp space expand again, giving the starship a boost of many orders of magnitude in the fantastical, but a new It seemed like the dream of faster- than-light travel had died. Inflation, dark direction the craft had been moving under experiment may just be the energy, the entire rest-mass energy of the impulse power. It’s like a rug being pulled visible Universe – these are forces of underneath you or, as physicist Eric Davis turning point needed to nature wildly bigger than anything we can at the Institute of Advanced Studies at Austin, Texas describes it, surfing on a transform fantasy into reality. control but since 1994 there has been a determined downsizing effort going on. By wave of space-time where the wave is revisiting Alcubierre’s calculations, doing the work, not the surfer. So a warp bubble could turn a velocity of a tenth the A laboratory experiment to test successive physicists have been able to twiddle with the initial conditions of the speed of light into ten times the speed of whether space can be artificially ‘warped’, light, making a journey to alpha Centauri potentially leading to a ‘warp drive’ for equations and reduce the amount of energy required, first down to the mass- 4.3 light years away last a mere 0.43 years, starships, has been designed by Dr Harold or just over five months. ‘Sonny’ White and his team at the energy of a galaxy, then a star and a gas advanced Eagleworks Labs at NASA’s giant planet. Now White has reduced the The reduction in the required energy Johnson Space Center in Houston. energy requirements to an amount that, from the days of Alcubierre is a result of at first glance, seems eminently toying with the thickness of the warp When limited to conventional physics, obtainable: about 500 kilograms, the mass bubble. The thicker this bubble is, the interstellar travel is really going to be a of the small family car that you drove to lower the energy density required, game for the patient explorers amongst work this morning. although this reduces the volume inside us. Chemical rockets and gravitational What would that energy do? Imagine the bubble and the optimum trade-off slingshots would propel probes on between volume and bubble thickness has interstellar journeys that take tens to you have a starship moving away from Earth under conventional propulsion at yet to be determined. However, before we hundreds of thousands of years. Even the get too excited, there are some quite mighty blast of a fusion-powered engine some sub-light speed – call it impulse power. Then the starship uses the energy formidable obstacles to overcome, not like Daedalus’ (see Page 9 for more) would least the energy requirements. Although still lead to journeys lasting decades or to activate its warp engine to create a ‘bubble’ of warped space around it. Inside the mass-energy of a car doesn’t sound too centuries. Those are realistic bad, in real terms it amounts to 10 19 expectations, but science fiction has given the bubble, everything is normal, with us the dream of travelling from star to star in a few weeks. Such dreams can be hard to shake. Albert Einstein showed that nothing can travel faster-than-light through space – but relativity doesn’t rule out space itself moving at incredibly fast speeds. We’re witnessing it today – dark energy is causing the expansion of the Universe to accelerate faster than the speed of light. In the very first fractions of a second after the big bang, the Universe experienced another burst of runaway growth thanks to inflation. In 1994, influenced by the science behind inflation, physicist Miguel Alcubierre, who was at Cardiff University at the time and today is at the National Autonomous University of Mexico, derived solutions to Einstein’s General Theory of Relativity that suggested it was possible to warp space for very rapid and perhaps near instantaneous travel across Could a warp drive enable faster-than-light travel? Image: NASA.

Principium | Issue 1 | December 2012 Page 4 joules, which is almost equivalent to the effects – no time dilation or length annual energy expenditure of the United It’s like a rug being pulled contraction. Inside the bubble the starship States. However, a civilisation that uses all underneath you, or a surfer on a wave would experience the same frame of available energy falling onto its planet of space-time where the wave is doing reference as we do here on Earth (or at from the Sun, boosted perhaps with the work, not the surfer. least one close to it if the starship were widespread use of fusion reactors, would already moving at a small fraction of the find such an amount of energy to be much Lab experiments speed of light before engaging the warp more realistic. bubble). Astronauts would not venture off Nevertheless, White has come up with to the stars and return only to find that More problematic is the type of energy, a way to test his theories in the lab. He’s centuries or perhaps millennia have and this is why we describe warp drive as designed an experiment called the passed on Earth as the soldiers in Joe unconventional physics – the warp bubble White Juday Warp Field Interferometer Haldeman’s novel The Forever War only works if negative mass and energy, that will use a helium-neon laser to experienced. Instead they could return produced by some exotic form of matter, is detect an artificially-created warping of home to find their loved ones have barely used. We have experienced negative space across a diameter merely one aged at all. energy both cosmologically, in the shape of centimetre across. The interferometer inflation and dark energy, and closer to will be able to detect a perturbation in It’s still early days and nothing has yet home in the Casimir Effect (the slight space-time as small as one ten-millionth been proven in the laboratory; some repulsive force created as a result of of a centimetre by monitoring the timing physicists are sceptical that Alcubierre’s vacuum energy – produced by virtual of the laser reflecting off mirrors and solutions would even work in real life. Yet particles popping in and out of existence passing through the warped space. If the if the solutions do work and if the huge thanks to the uncertainty principle of warp bubble created in the experiment problem of the large quantities of exotic quantum mechanics – between two metal were around a spacecraft, it would boost negative energy can be solved, perhaps our plates marginally separated). But its velocity by 1.0000001 times. private fantasies of a Star Trek future can accessing large quantities of negative be achieved after all. energy, storing it and then utilising it are The beauty of a warp drive, if it could all currently problems without answers. work, is that there would be no relativistic

News from alpha Centauri

News of the nearest exoplanet to home has raised the stakes among hunters of alien worlds. Have starship, will travel – but to where? The destination for our intended interstellar craft is going to be a crucial piece of the jigsaw – too far away and we won’t be able to get there, too inhospitable and there will be little to attract us. A potentially habitable planet orbiting one of the Sun-like stars in the alpha Centauri system, the closest to our Sun at a ‘mere’ 4.3 light years distant, would by the culmination of two decades of exoplanet- hunting and now a new discovery takes us part of the way there; a planet, slightly more massive than Earth, orbiting the star alpha Centauri B. “There’s not been a more exciting result for an individual star, even with the long line of spectacular results from the last two decades,” says Professor Debra Fischer of Yale University. “The indication that our nearest neighbour has rocky planets is incredible!” An artist’s impression of the alpha Centauri system. Alpha Centauri B and its attendant Fischer leads a team that has been planet are in the foreground, with alpha Centauri A to the lower left and our Sun a bright star in the upper right, 4.3 light years away. hunting for planets around alpha Image: ESO/L Calçada/N Risinger (skysurvey.org). Centauri for several years, but her group

Principium | Issue 1 | December 2012 Page 5 were beaten to the discovery by European be common, points out Professor Greg “It’s twice as easy to get there than astronomers mostly based at Geneva Laughlin of the University of California, other stars.” Observatory using the HARPS (High Santa Cruz. In our neighbourhood of the Galaxy Accuracy Radial velocity Planet Searcher) “There is nothing unusual about this stars are, on average, distributed four light instrument fitted on the 3.6-metre planet,” he says. “Around fifty percent of years from one another, but most of those telescope at the European Southern the stars in the solar neighbourhood have stars are cool red dwarfs or dim, dreary Observatory in Chile, which has pushed close planets smaller than Jupiter so, no brown dwarfs. It is quite unusual for two our exoplanet detection abilities to the offense to the Geneva team, but this Sun-like stars to be so close – and in the limit. HARPS is a spectrometer that is planet is completely run of the mill!” alpha Centauri system we have the bonus able to detect slight ‘wobbles’ in the star of two Sun-like stars. caused by the gravitational perturbations So why does it excite those of us who of accompanying planets. In the case of share an interstellar vision? It’s not the “The odds that we would have such an alpha Centauri Bb, as the new planet is planet itself, but what its presence extraordinary star so close to us is one in a known, the wobble it induces in its parent potentially promises. “It turns out that thousand,” says Laughlin. “A million star amounts to a movement of no more most of the low mass planets are in years ago alpha Centauri was far away than 51 centimetres. systems of two, three or more planets, all and not visible; in another million years the way out to the habitable zones,” says it will have passed by. Right now is its Lava oceans Stephane Udry of Geneva Observatory. closest approach.” “So there is a very large probability that Alpha Centauri Bb orbits its star at a Naturally any potentially habitable distance of just 5.98 million kilometres – there are more planets around alpha Centauri B.” worlds will also be of interest to SETI, close enough to fall into gravitational step the Search for Extraterrestrial with its sun and become tidally locked so Reasons to go Intelligence. “At just four light years that it always shows the same face to its away a technological civilisation, if it star. Consequently there is no hope for If indeed more planets exist, possibly in existed, would be watching recent news oceans of water; the dayside will bear the the habitable zone, alpha Centauri from Earth,” says Fischer. So as we brunt of the star’s heat, its surface melting becomes a hugely attractive destination. watched President Obama being re- in temperatures up to 1,220 degrees “If a potentially habitable planet is found elected, denizens of Alpha Centauri would Celsius. Rather, oceans of lava will be the we might see a groundswell of excitement order of the day. Such worlds, where the be witnessing the run-up to his triumph to look towards new propulsion molten surface evaporates to form a thin in 2008, and watching Spain beat all technologies that can get a probe there silicate atmosphere, or exosphere, have before them in the UEFA European been found by the Kepler space mission to within a human lifetime,” says Laughlin. Football Championships. Second Earth? A possible planet, seven times more of the solar heating that Earth receives planet is too massive – recent work by massive than Earth, has been found from the Sun. In order to be potentially MIT’s Vlada Stamenkovic indicates that sitting smack-bang in the habitable zone habitable, it will need an atmosphere such super-earths could possess interiors of a star 42 light years away. The system, thicker than Earth’s to trap the heat, but that have not separated into a core and HD 40307, is home to six planets, all such a massive planet (the surface gravity mantle, therefore ruling out protective rocky ‘super-earths’, but it is planet g that would be almost twice that of Earth) magnetic fields created by a dynamo has captured the imagination the most. should have no problem retaining a effect within the planet, and the churning Discovered through re-analysis of data thicker atmosphere to ensure of continents through plate tectonics that from the world’s greatest radial velocity temperatures appropriate for liquid is vital for recycling carbon and planet detector – the HARPS instrument water. The main problem may be that the regulating planetary temperature. at the European Southern Observatory in Chile – by a team led by Mikko Tuomi of the University of Hertfordshire, 40307g orbits its orange K-class star (which is cooler than the Sun) every 198 days at an average distance of 90 million kilometres, or about 0.6 astronomical units (where one astronomical unit is the mean distance from the Sun to Earth, 149.6. million kilometres). Although unconfirmed at present until other astronomers are able to detect it independently, if it does exist it may be the closest thing to Earth found so far. The star’s habitable zone exists between 0.43 and 0.85 astronomical units All the potentially habitable exoplanets discovered thus far, compared to Earth and and planet 40307g will receive 62 percent Mars. Image: PHL@UPR Arecibo.

Principium | Issue 1 | December 2012 Page 6 The billion-year plan in the Asteroid Belt that could potentially become home to 100 trillion Maybe the century-long outlook of I4IS humans. However, it’s a more pressing and other interstellar groups is too short? race against time than it at first glance Writing on the website KurzweilAI.net, appears – with just a few hundred years Lt Col Peter Garretson, Chief of Future of natural resources remaining on Earth, Science and Technology Exploration for and other looming crises such as the the United States Air Force, believes we environment or war, we need to develop a should start planning now for the far space programme based around the long- future and the billions and trillions of term survival of humanity now, before it years to come. is too late. “It isn’t enough just to plan for two or Even the Sun won’t last forever, with 20, or even the fabled Chinese 100 year Garretson recognising the need for periods,” he writes. “We need to be interstellar colonisation – the further we thinking and planning on the order of spread ourselves, the greater the billions of years. Our civilisation needs probability that some will survive. inter-generational plans and goals that He even speculates towards the end of span as far out as we can forecast the Universe, when the stars go out, significant events.” atoms decay and the black holes When the Sun goes out and expands The first of those events include the themselves begin to evaporate, leaving into a red giant before billowing away uninhabitability of Earth within a billion one possible door open to us – the into a planetary nebula some five years as the Sun warms. Garretson creation of new, baby universes into billion years into the future, such as the which we could escape. Helix Nebula pictured here, humanity proposes that we build giant O’Neill will have to move on to other stars to colonies (named after the NASA You can read the full article at survive. Image: NASA/ESA/C R Dell astrophysicist Gerard O’Neill who http://www.kurzweilai.net/what-our- (Vanderbilt University)/ M Meixner/P popularised the idea in the 1970s in his civilization-needs-is-a-billion-year-plan McCullough. book, The High Frontier) from material

Spectroscopic SETI During our interstellar travels it is feasible that we’ll bump into other intelligent species out there, but perhaps we will have discovered their existence beforehand. One way to do this could be to detect signals from them, perhaps in the form of powerful laser pulses. Currently, unlike searches for radio signals from extraterrestrial civilisations in the form of all-sky surveys, optical searches for lasers have to take the slow road, going from star to star. Now Ermanno Borra of Université Laval, Québec, might have a solution. He points out that a pulsating laser source modulating its frequency over periodic time periods as small as 10 –10 to 10 –15 seconds would be detectable as frequency shifts in astronomical spectra, of the kind routinely taken by all-sky spectroscopic surveys of stars such as the Sloan Digital Sky Survey in New Mexico. These surveys produce huge amounts of data, much of it barely analysed, which scientists could sift through searching for anomalous frequency patterns that might be indicative of an alien calling card. Borra’s report is published in the The 2.5-metre telescope of the Sloan Digital Sky Survey (SDSS) at Apache Point in Astronomical Journal and a pre-print can New Mexico could theoretically discover laser signals from intelligent extraterrestrials be found here: during its all-sky spectroscopic surveys designed primarily to measure the redshift http://arxiv.org/abs/1210.5986v1 and hence distance of galaxies and stars. Image: Fermilab Visual Media Service.

Principium | Issue 1 | December 2012 Page 7 a million pounds. Basically launching a cubesat is like sending a bag of sugar into space – similar size, same mass – except that the cubesats can be combined into configurations of two or three ‘units’, or 2U or 3U in the shorthand notation of the growing cubesat community. The first cubesat to reach orbit launched on a Russian Soyuz rocket in June 2003 and since then another 74 have followed it into space. Far from the THE GREAT CUBESAT REVOLUTION training exercises they were envisaged as, scientists are now using them as low- budget options for their research. end of the scale a fusion-based propulsion Tiny cube-shaped satellites The first British cubesat, a 3U system only rates a two and a warp drive, configuration called UKube-1, will carry where not even the theory is nailed down, weighing just a kilogram are five experiments including one to has a TRL of one. The only way we can demonstrate the feasibility of using cosmic making space exploration increase their TRL is by testing, ray hits to generate random numbers that experimenting and optimising them for affordable and they may can be used to secure communication use in future missions and, perhaps one links. It will blast off on a Soyuz rocket in ultimately provide the first day, an interstellar voyage. March 2013. precursor missions for what Project CATSTAR seeks to take will eventually be a voyage to cubesat technology and apply it to developing the science for interstellar another star system. travel, but there is no need to rush. Cubesats fall into the natural scheme of Big dreams start small. The first space science and engineering, coming after mission that the Institute for Interstellar theory, table-top experimentation and Studies ™ will launch won’t be a fusion- fully-fledged ground demonstrations. powered starship to Fomalhaut; it won’t If a cubesat mission is successful the next be a graceful solar sail to Sirius; it won’t step is to utilise the technology in a even be an automated probe to alpha precursor missions to the other planets in Centauri. In fact, the Institute’s first the Solar System or perhaps to the outer mission won’t even reach beyond boundary of the Sun’s influence in the NASA’s NanoSail-D2 cubesat was a distant Oort Cloud of icy cometary Earth orbit or be larger than a few testbed for solar sail technology that bodies. From there it is but a giant leap bags of sugar. one day may aid the voyage of an interstellar craft. Image: NASA. for a real mission to the stars. Project CATSTAR is the Institute’s From small seeds do great things grow programme to launch a cubesat, which are and, if the first interstellar missions That’s where cubesats come in. We small satellites built from off-the-shelf do carry technology that was initially might not be able to test an antimatter electronic components, no larger than 10 tested in diminutive cubesats, it will drive in a cubesat, but we can test solar centimetres cubed and sometimes stacked be symbolic of our growth from small sails for example – NASA’s NanoSail-D2 in twos or threes, piggybacking on rocket scale space missions to conquering mission in 2010 utilised a cubesat-like launches delivering other satellites into interstellar distances. space to keep launch costs down. The idea satellite from which unfurled a ten-metre is to use the cubesats – built by Institute square sail made from kapton film just scientists, engineers and team-members – two microns thick. There are also other, to test new technologies necessary to less dramatic, applications, from testing begin building the foundations of an radiation shielding, communications interstellar craft and, by doing so, systems and software, or even used as a increasing what is termed their telescope for detecting transiting Technological Readiness Level (TRL). exoplanets as in the case of MIT’s ExoplanetSat launching some time in the Get ready next 12 months. The TRL is a measure of how advanced Mission training a specific technology is. An ion drive, for instance, has the highest TRL rating of Cubesats had a modest beginning. nine, implying it has been fully tested on Initially developed by Jordi Puig-Suari at successful missions, such as the European the California Institute of Technology and Space Agency’s SMART-1 mission to the Bob Twiggs at Stanford University in the Moon or, more recently, NASA’s late 1990s, they were intended as training extraordinarily successful Dawn mission platforms to give students the opportunity to the asteroids Vesta and, in 2015, Ceres. to practice building, testing and operating Three small CubeSats are deployed Solar sails have a TRL of eight, indicating low-cost spacecraft. A single cubesat can from the International Space Station on they have been flight tested but not put to set you back as little as £50,000 and even 4 October, 2012. Image: NASA work on any real missions yet. At the other the most expensive rarely top a quarter of

Principium | Issue 1 | December 2012 Page 8 Retrospective: Project Daedalus

The greatest starship design Daedalus blueprints was for it to be An unmanned probe that would completed within the working lifetime of isn’t the Enterprise or a Star accelerate to 12 percent of the a mission scientist. To these ends, speed of light, whizzing past Daedalus was designed to keep things Destroyer, but Daedalus – a Barnard’s Star. simple, with an unmanned probe that real attempt at creating a would accelerate to 12 percent of the Dreams, however, are not particularly speed of light, whizzing past its target blueprint for a vessel that scientific. Led by Alan Bond, a group of destination (Barnard’s Star) and returning skilled enthusiasts sought to remedy this. data to Earth. could travel to one of the Science fiction, from the popcorn Golden nearest stars and beyond at 12 Age classics of E E ‘Doc’ Smith to the Fusion power to the stars more refined ‘hard’ SF of Arthur C Clarke percent the speed of light. or Isaac Asimov, regularly portrayed Nuclear fusion was the power system of interstellar travel as a natural progression choice for the spacecraft in the 1970s and of human ingenuity, but was it really even today, when interstellar spacecraft We at the Institute for Interstellar possible to go galavanting around the designs are discussed, fusion propulsion is Studies™ fiercely believe that starship Galaxy like Captain Kirk? Moreover, the often top of the list. Daedalus was to carry building will be a major part of the future answer would solve some riddles about our ten tanks of tiny pellets composed of of humankind, but what many may not own future and the apparent absence of deuterium and helium-3, around 54,000 realise is that to reach the future much of extraterrestrial life in the Galaxy; if tons in total, equating to a total of 30 our inspiration is going to come from the interstellar travel was inordinately hard, billion pellets. When bombarded with past. For in the 1970s, members of the we could not reasonably have expected electron beams these pellets would British Interplanetary Society aliens to have reached our planet, neatly undergo nuclear fusion, producing energy, accomplished something that had never answering the puzzle of why we see no helium-4 and protons that would be before been achieved, something evidence of intelligent extraterrestrial directed by magnetic nozzles out through revolutionary: the design of a starship. life close to Earth. On the other hand, if the engine to provide thrust. By igniting interstellar flight was achievable, it could 250 pellets per second Daedalus would Interstellar dreams 13 raise more concerns about where produce 10 watts – around one It was 1973 and the promised land of everybody is. megajoule per pulse – to power the regular spaceflight throughout the Solar starship out of the Solar System. And so Project Daedalus was born: a System and the untold riches that it could The tank layout is a vital part of bring were still in sight. Apollo had ended five-year study to produce a solid, scientific design for an interstellar craft, bringing Daedalus’ design. Like the Saturn V or the a year previous, with the United States space shuttle’s external tank and solid embroiled in a war it could ill afford, but the dreams of SF into the realm of hard calculations using 1970s technology or rocket boosters, Daedalus would be a the talk was of more ambitious missions: multi-stage system. Six tanks, in total permanent space stations, colonies on the near-future tech, extrapolated from where science and engineering was at in 1973. carrying 50,000 tons of pellets, would form Moon and flights to Mars. Such talk led to the first stage, with two tanks dropping dreams of how far we humans could go. Beyond this the only other requirement for any mission launched based on the away after 250 days of powered flight, having reached a distance of 0.0039 light years from the Solar System. Another tank is left behind at 0.0178 light years, another at 0.0503 light years and then just over two years into the mission the entire first stage is discarded into interstellar space, having driven the starship up to seven percent of the speed of light. Without the redundant mass of the first stage and its empty tanks, the 4,000 tons of propellant in the second stage doesn’t have to work as hard, burning for 320 additional days, ending three years after leaving the Solar System at a distance of 0.21 light years. Daedalus would then continue the rest of the way coasting at 12.2 percent of the speed of light (36,500 kilometres per second) for around 46 years. There is no

Principium | Issue 1 | December 2012 Page 9 produce it ourselves in reactors on Earth If we can realise the technological (through deuterium/deuterium or Project Icarus steps in nuclear fusion and electronics, lithium-6/neutron reactions, but this is predicted by reasonable extrapolation costly and time-consuming), collect it In Greek mythology Daedalus had a of today’s technology, then interstellar from the solar wind (where we would need son, Icarus. Both built wings of wax, missions of a limited type an enormous and impractical collecting but Icarus flew too close to the Sun will be possible. area) or on the Moon where the solar wind deposits it (but the concentrations and the wax melted, sending him are low), or head out to Jupiter and mine plummeting to the sea below. reason why the starship could not have it from its atmosphere (requires a space- Project Daedalus has also based society and an interplanetary even more stages, producing higher bequeathed Project Icarus, a velocities, but even then we are still infrastructure). Perhaps surprisingly, looking at many decades travel time with Jupiter was the preferred choice of the twenty-first century design-study for Daedalus before we reach the nearest Daedalus team, who imagined that the an interstellar vehicle. stars. As the Daedalus report described starship could be built nearby the Jovian Once again initiated by members of in a special edition of the Journal of the fuel depot, the manifestation of a wealthy, the British Interplanetary Society, British Interplanetary Society in 1978, Solar System wide society mining and “A complete mission would involve about transporting helium-3 for use in fusion originally headed up by I4IS 20 years design, manufacture and vehicle reactors on Earth and in various colonies. Executive Director Kelvin Long, checkout, 50 years flight time and six to The study concluded that, “If we can Icarus began as a five-year study – nine years of transmitting information realise the technological steps in nuclear now in its penultimate year – but has back to the Solar System. Therefore, fusion and electronics, predicted by since taken on a life of its own as it appears that even the most simple reasonable extrapolation of today’s interstellar missions will require a technology, then interstellar missions of a the foundation for a non-profit commitment of support for 75–80 years... limited type will be possible.” This modest organisation called Icarus Even if the exhaust velocity of the rocket judgement perhaps belies their ambition Interstellar, dedicated to interstellar could be doubled, thus permitting and optimism in embarking on the project deceleration at the target, flight times – the degree to which we can become an flight and initiating many projects would still be measured in decades and so interstellar civilisation remains to be seen, into deep space propulsion. To find manned interstellar flight does not look but Project Daedalus certainly bolstered out more, visit very promising.” hopes rather than constrained them. www.icarusinterstellar.org. Problems with power Barnard’s Star, which is a red dwarf star 5.9 light years away and which has Even unmanned interstellar flight using the highest proper motion of any star on the Daedalus system currently faces two the sky, seemed a good choice of Jargon Buster big problems. The first is nuclear fusion destination in the 1970s as circumstantial itself. Regardless of the type of fusion – evidence pointed to the existence of whether it be electron beams, inertial planets in orbit around the star. Alas, that Helium-3/helium-4 confinement fusion (ICF) with high- evidence turned out to be false, but with powered petawatt (10 15 watts) lasers These are differing isotopes of atomic planets now being discovered in the alpha or a magnetic confinement reactor with helium. Helium-3 has one neutron and Centauri system our nearest star system tokamaks containing a plasma of two protons; helium-4 has two is looking a much more promising target. deuterium and tritium that is heated to neutrons and two protons. a million degrees until the atoms fuse – Wherever its destination, after the fly- Nuclear fusion no fusion reactor has yet produced more by Daedalus was fated to never return energy than is put into the system. home. It would carry on deep into The process by which two atomic For example, the best the Joint European interstellar space, continuing to do nuclei are fused together to form a Torus magnetic confinement reactor in science in the interstellar medium as long larger nucleus, releasing energy in Oxfordshire, UK has achieved is a 16 as power and communication with Earth the process megawatt output for two seconds held out. Had it flown to Barnard’s Star, Fermi Paradox following an input of 25 megawatts. its trajectory would eventually have taken However, technological advances in it about 13,500 light years above the This conundrum asks, if intelligent tokamaks and ICF should remedy this Galactic Centre in about 180,000 years extraterrestrial life exists and if problem within the decade and it is time and ultimately out of the Galaxy – interstellar travel is possible, why has expected that by 2050 a substantial from being our first interstellar explorer Earth not been already colonised by proportion of the energy on the to becoming lost in intergalactic space, aliens at some point in its 4.5 billion National Grid will come from commercial Daedalus’ voyage would become the years history? Where is everybody? fusion reactors. greatest adventure of all time. Project Daedalus aimed to inform the Fermi Paradox discussion by showing So that’s one problem solved; the whether interstellar flight was possible other is going to take a bit more work. or not. You’ll notice that in Earth-based reactors deuterium and tritium are used as the Light year reactants, whereas in Daedalus deuterium The distance light travels in one year, and helium-3 is preferred. That’s because which is 9.46 trillion kilometres. helium-3 is a more efficient fusion fuel. Barnard’s Star is 5.9 light years away, However, it is rarely found on Earth. If we The British Interplanetary Society or 55.8 trillion kilometres. want access to helium-3 we must either http://www.bis-space.com

Principium | Issue 1 | December 2012 Page 10 The Daedalus Starship

Probes Deflector shield Daedalus wasn’t designed to slow down, Powering through space at 12 percent of the speed of light requires a clear so its visit to Barnard’s Star would be path – hitting even the tiniest piece of space dust at that velocity would fleeting, passing through at 12 percent the pack the punch of an atomic bomb. speed of light. In order to better study the star system, Daedalus would deploy 18 In order to protect the ship a deflector shield must be employed in front of scientific probes to investigate the star the vessel in the form of a cloud of micron-sized dust particles that would and any attendant planets closer up. intercept anything from dust to small asteroids up to 500 kilograms and vapourize it on contact .

Stages The Daedalus starship is divided into two stages to allow increased velocity by losing mass during the journey. The first stage consists of six tanks of propellant and is discarded after two years; the second stage has four smaller tanks that provide added propulsion for a further 320 days.

Self-repairs Even the most sophisticated systems with built-in redundancy will inevitably suffer breakdowns at some stage during such a long and arduous mission. Without humans on hand to make repairs, two Power robotic wardens, armed Superconducting coils with a degree of artificial generate a magnetic field into intelligence necessary which the deuterium/ helium-3 to be able to function pellets are injected to collide autonomously six with beams of electrons inside light years from the reaction chamber and home, will patrol fuse, the products of which the starship during are magnetically driven out to the voyage to provide thrust . maintain the vehicle and implement repairs.

Communication For short range signalling, either with its daughter probes or with Earth during the first stage of propulsion, Daedalus was to be armed with a high-power laser. A radio antenna – made out of the parabolic dish of the second stage’s reaction chamber – would be used for longer distance communication. However, during the 1970s lasers were still an immature technology, less than two decades old. Dimensions Today lasers are considered a far superior mode of long One hundred and ninety metres distance communication. long, Daedalus would not be an especially giant starship – the fictional starship Enterprise was 300-metres long – but it is still far larger than any spacecraft or space station built to date. Its sheer size requires that Daedalus would have to be assembled in space.

Principium | Issue 1 | December 2012 Page 11 Book Reviews Going Interstellar Council Chair Dr Gregory Matloff, Icarus Lights to the Land of Snow’ is the only real Interstellar’s Richard Obousy and Johnson letdown, a meandering and unfocused Edited by Les Johnson and Jack McDevitt himself. Indeed, amidst all these stellar novella about the reincarnation of the names it’s Johnson who gets the book off Dalai Lama onboard a Tibetan colony ship This isn’t the first the starting block with a contender for the that lacks a strong climax. starship anthology to best short story within its pages, ‘Choices’, The accompanying essays are put the science into where the use of virtual reality as a tool to comparatively brief and are aimed mostly the fiction, and it stimulate the mind during hibernation at the newcomer to starship and won’t be the last, but threatens to derail an interstellar colony propulsion physics, but they are concise it is certainly one of mission. The main character’s solution is and surprisingly comprehensive overviews the best. Proclaiming ingenious, to say the least. ‘Build Starships of solar sails, antimatter and fusion Now!’, every page Also worthy of mention is McDevitt’s starships. Overall, Going Interstellar’s fizzes with bold ideas ‘Lucy’, a charming tale of artificial innovative and engaging prose and essays and clever use of intelligence and curiosity versus are packed with enough thought imagination. stagnation. Bova equips himself well in ‘A provoking ideas to make it a real winner. Country for Old Men’ in which an old Which you would expect from the scientist feeling redundant onboard a pedigree on show. Les Johnson is Deputy starship crewed by young people and an AI Going Interstellar Manager for NASA’s Advanced Concepts finds a new reason for existence in Authors: Michael Bishop, Ben Bova, Charles Office at the Marshall Space Flight navigating the hydrogen fields of the E Gannon, Sarah A Hoyt, Les Johnson, Center; Jack McDevitt is a celebrated SF interstellar medium. Meanwhile, Gannon’s Louise Marley, Gregory Matloff, Jack author with Nebula and Philip K Dick ‘Lesser Beings’ exists in a Universe where McDevitt, Richard Obousy, Mike Resnick awards under his belt. Together they’ve humans have already colonised the stars accumulated some of the best starship and oligarchic houses engage in conflict Published by Baen (paperback, 416pp) fiction around, headlined by the great SF and introduces a new motivation for veteran Ben Bova and including Charles interstellar travel: expulsion. Sarah Hoyt’s ISBN: 978-1-4516-3778-6 Gannon, Louise Marley, Michael Bishop, ‘The Big Ship and the Wise Old Owl’ is a Available from Amazon . Sarah Hoyt and Mike Resnick. slightly contrived look at ensuring the Interspersed between are essays on real crews of generation ships don’t lose sight of starflight concepts from I4IS’ Advisory their goal while Michael Bishop’s ‘Twenty

Deep Space Propulsion the book really earns its stars to become technologies and, as a result, the text here the very roadmap that Long asks for feels uneasy, listing facts about the planets Kelvin F. Long within its pages. His (self-confessed) that needn't be in a book about propulsion. optimistic timeline on page 321 has That aside, Deep Space Propulsion is an The first few chapters technology demonstrator missions blasting otherwise excellent guide to starship move rapid-fire off in the next few decades, sending a design and the chapters, replete with through many pathfinder probe to 1,000 astronomical practice exercises at the end of each different propulsion units (the outer edge of the ‘focal point chapter (and not all of them are systems (21 variations zone’ where the Sun can be used as a mathematical, giving readers of all in all) and reasons gravitational lens); the first interstellar abilities a chance at having a go) almost why we should dream probe launches in 2100 to arrive at a seem to have been arranged to suitably of interstellar travel. nearby star (possibly the alpha Centauri fit a lecture course on the topic. If you In subsequent system) by 2160 and the launch of the first have the time, this ‘homework’ is well chapters Kelvin Long, human interstellar colonising mission by worth the effort and is a really nifty idea I4IS’ Executive Director, expands on these 2250. To put this into context, popular on behalf of Long. systems, rigorously describing the science fiction such as the original Star For anyone with a serious interest in workings of electric and nuclear-based Trek and Babylon 5 are set around the 2250s the subject, Kelvin Long's essential book propulsion, fusion drives, solar sails and and Long notes that without a may be the best around. the possibilities of antimatter and Bussard breakthrough discovery that could ramjets, charting their development all revolutionise space travel, such as warp the way back to basic flight principles. drive or wormholes, meeting the These rigorous workings include many expectations of those SF tales is going to Deep Space Propulsion mathematical proofs, but the non- be difficult. Author: Kelvin F. Long mathematical enthusiast shouldn't be put off - it’s good to try and follow the maths, Long hits his stride best when Published by Springer (paperback, 367pp) although for the general reader it isn't discussing the overall structure of ISBN: 978-1-4614-0606-8 essential and can be skipped over. mounting an interstellar mission; on the e-ISBN: 978-14614-0607-5 other hand, some early chapters about Long goes beyond propulsion exploring the Solar System and beyond Available from Amazon. technologies to look at general mission seem rather incongruous amidst the design and architecture, which is where discussion of propulsion and mission

Principium | Issue 1 | December 2012 Page 12 The young star cluster NGC 3603 in We'd love to hear from you, our readers, Carina. Image: NASA/ESA//R O’Connell about your thoughts on Principium, the R IN (University of Virginia)/F Paresce (National Institute or interstellar flight in general. O T F E R Institute for Astrophysics, Bologna) / E S Join us on our Facebook page to join in T T E Young (Universities Space Research U E the conversation! T

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