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Colonizing the Galaxy Using World Ships

The British Interplanetary Society’s Kelvin Long is no stranger to these pages, perhaps best known as the founder and first leader of Project Icarus, but an indefatigable writer on interstellar topics as well. Kelvin’s first book, Deep Space Propulsion: A Roadmap to Interstellar Flight, is scheduled for publication by Springer later this year. Fellow writer Pat Galea has a background in electronic engineering and physics, and has been a professional software engineer since 1993. As well as contributing to the Project Icarus starship design, he is a supporter of Monkey World in the UK, and a staunch advocate for preserving Bletchley Park, home of World War 2 code breaking. Both Long and Galea are Tau Zero practitioners as well. The duo here offer us an overview of a symposium Kelvin recently organized in London that as far as I know was a first: A conference entirely devoted to the breathtaking concept of interstellar colony craft potentially hundreds of kilometers long.

by Kelvin F. Long & Pat Galea, Symposium Chairmen

On the 17th of August 2011, a gathering devoted to the colonisation of space assembled at the headquarters of the British Interplanetary Society (BIS) in London. The society has been the home of visionary research for many years and has never been afraid to allow free thinking speculation on the future of man in space. The topic of conversation for this symposium was the concept of a World Ship. The reference is to a very large vehicle many tens of kilometres in length and having a mass of millions of tonnes, moving at a fraction of a percent of the speed of light and taking from hundreds of years to millennia to complete its journey.

A worldship is self-contained and self-sufficient, carrying a crew that may number hundreds to thousands and might even contain an ocean, all directed towards an interstellar colonisation strategy. Several seminal papers on the topic were published in 1984 by Anthony Martin and Alan Bond. They developed a ‘wet’ World Ship concept 10 km in diameter, nearly 200 km in length, on the order of a peta-kilogram (1015 kg) habitat mass and an equivalent mass in propellant. The biggest of the ‘dry’ World Ship concepts they developed had a diameter of 15-20 km, and was around 220 km in length. The habitat mass was an order of magnitude lower than the wet concept but the propellant mass was similar in magnitude. These are obviously massive vessels and they would travel to the stars with cruise velocities of around 0.5% of the speed of light, taking hundreds of years to reach the nearest stars.

Image: Conference organizer Kelvin Long.

In one of these papers, Martin had this to say:

“The World Ship concept has now evolved to a stage where it needs to be subjected to more searching analysis. The technological and engineering aspects need to be re-examined in more detail… If the World Ship concept survives this scrutiny intact, even if modified in detail, then the fundamental questions raised by the possibility of interstellar travel and colonisation about the apparent absence of extraterrestrial intelligence in the Solar neighbourhood, about the future of mankind, and about its place in the Universe will become more demanding of an answer.”

The recent conference at the BIS included seven presentations discussing the technology, motivations, financing and cultural interactions of communities aboard such a large space vessel. In this article a brief synopsis of the presentations is given, all of which will shortly be submitting for publication in a special issue of the Journal of the British Interplanetary Society (JBIS), further contributing to the important literature of interstellar studies.

The Enzmann Starship

Kelvin Long, a Project Icarus designer, gave a presentation on “The Enzmann Starship: History & Engineering Appraisal,” on behalf of his co-authors Adam Crowl and Richard Obousy. The history of the concept was clarified and it was revealed that a communication with Robert Enzmann had been established. Most remarkable was the fact that Enzmann claims he first thought of the concept in 1949. Every drawing or painting known to exist on the concept was presented to the audience and some of the subtle design changes pointed out. The important role that Rick Sternbach and Don Davis had played in developing the engineering concept, and G. Harry Stine’s in publicising it, was emphasised. Some preliminary engineering calculations were shown on the authors’ understanding of the Enzmann Starship (or Slow Boat): A 30,000-tonne habitat structure with 3 million tonnes Deuterium fuel, travelling a cruise speed of 0.09c (27,000 km/s) on a 60-year journey to the stars. Large scaled versions were also shown as developed by the authors for the symposium, including a 300,000-tonne Slow Ship travelling at a cruise speed of 0.045c (13,500 km/s) on a 150-year journey, and a 3,000,000-tonne World Ship travelling at a cruise speed of 0.014c (4,200 km/s) on a 350-year journey.

The three concepts would start with 200, 2,000 and 20,000 people respectively, but grow by the end of the journey to 2,000, 20,000 and 200,000 people. The mass distribution with the growing population throughout the trip (i.e. ship mass per person) varied from 150 tonnes/person to 15 tonnes/person at the journey’s end, emphasising the need to attempt planetary settlement in some form. Long pointed out that previous NASA space settlement studies had indicated a distribution of around 65 tonnes/person was desirable. The Enzmann Starship was seen as a fascinating idea and the presenter claimed that Robert Enzmann deserved equal recognition with the “other Bobs” in interstellar studies, namely Robert Forward, Robert Bussard and Robert Frisbee.

Image: The October, 1973 issue of Analog featured a gorgeous Rick Sternbach cover of two Enzmann starships to illustrate G. Harry Stine’s article, “A Program for Star Flight.”

Communicating with the Diaspora

Pat Galea, also a Project Icarus designer, gave a presentation on “Communications Between Worldships” or ‘building the Diasporanet’ as the speaker called it. He firstly gave an overview of the Project Daedalus communications systems and described the historical Project Cyclops which was intended for SETI research, but which the Daedalus designers proposed to use for long distance signal reception. Using a 40 m diameter transmitting antenna, with a 1 MW power output, Daedalus could download data to Earth at a rate of 864 kbps (kilobits per second) over a distance of 6 light years. Modern lasers over this distance would have a data rate equivalent to around 10 bps using a 20 W power output, although this could be increased to around 500 kbps using a 1MW power output, but the major advantage of using lasers is that the physical sizes of the transmitting and receiving elements could be much smaller than those used for Radio Frequency signals.

Two network topology configurations were described for World Ships moving outwards radially from a single point (i.e. Earth): multiple connection, in which each World Ship could communicate with Earth and other World Ships directly, and the ‘Star’ topology, in which each World Ship can communicate only with Earth. Galea then described the exciting possibility of using the Sun as a gravitational lens, with a signal relay craft located beyond the minimum ‘focusing’ distance at 550 AU (based on an idea extensively studied by Claudio Maccone). This provides a way of improving the reception of signals from distant World Ships significantly, drastically improving the data rate. To tackle the severe challenge of keeping the relay craft on track (on the order of meters of accuracy), each World Ship would send extremely bright—but very short—‘sync pulses’ back to a constellation of Navigational Satellites (NavSats) in orbit around the Sun. By comparing the very slight timing differences of the pulse arrival at each satellite, the NavSats could assist the relay craft in maintaining its track, and thus keeping a lock on the signal being received from the World Ship. As the Earth is acting as a router, passing messages back and forth between the World Ships, this system forms the basis of an interstellar internet, or “DiasporaNet”.

Image: Project Icarus designer Pat Galea.

The Worldship and the Sail

Galea then gave a presentation on behalf of Greg Matloff, who could not make it to the meeting. The presentation was on “World Ships: The Solar-Photon Sail Option.” It was argued that an ideal propulsion option for World Ships is the hyper-thin solar-photon sail, and that this is the only known ultimately feasible interstellar propulsion system that can also be applied for en-route galactic-cosmic ray shields as well as for acceleration and deceleration. The author reviewed three options for sail configurations known as Parachute, Hollow-body and Hoop Sails.

It was argued that although World Ship expeditions may not be likely from the present day Sun using solar-photon sail technology, they would be more feasible as the Sun evolves on and beyond the main sequence. Finally, the author raised the tantalising possibility that future space telescopes may be capable of imaging habitable planets circling near stars which have Solar-photon sail propulsion craft departing the system. The solar-mass type star Pollux at 35 light years was suggested as one location where we could search for evidence of a migration underway. In discussions after the talk, Alan Bond made the comment that using sails for World Ships is prohibitively difficult due to the issues of controlling the large number of oscillations in the sail while in flight. Kelvin Long argued that artificial intelligence technology could take care of that issue, though Bond countered that any smart technology in the sail would add to the mass, making the sail less effective.

Reliability in Deep Space

Andreas Hein, another Project Icarus designer, gave a presentation on “World Ships – Architectures & Feasibility Revisited.” The paper was co-authored with Mikhail Pak, Daniel Pütz, Christian Bühler and Philipp Reiss. The speaker first considered the mean distance to habitable planets, including a 140-light year estimate by Alan Bond, 88-light year distance by Claudio Maccone, and 33-light year distance from Kepler mission data. He considered the definition of a World Ship, and defined three criteria: self-sufficiency (thousands of years), population size (>100,000) and speed (<0.01c). One interesting aspect of the authors’ work was the consideration of reliability and mission success, with modelling performed to address this question. Hein concluded that 99.99% reliability was achievable provided sufficiently large scrap stock was made available for the mission. If the ship had a low reliability, then this could be compensated by sending many such vessels together.

Hein then considered migration push and pull factors. Push factors were defined to be scenarios such as war, genocide and poverty. Pull factors were defined to be education, job opportunities, security, stability, wealth. Finally, potential mission architectures were then considered including a complete trade space of population size, trip time and energy requirements. Hein said that one of the things which would determine the launch of a World Ship was the testing of several prototype vehicles first. He concluded that the mission architecture strongly depended on the habitable planet distance and that self-replication factories and advanced artificial intelligence would likely be requirements for World Ship technology.

The Worldship Rationale

Gerry Webb, a member of the original Project Daedalus Study Group, gave a presentation on “Why World Ships? An Enquiry into the Idea of World Ships and the Nature of Their Sponsoring Cultures.” The speaker first discussed definitions of World Ships and explored the science fiction literature. He said that the 1984 Anthony Martin and Alan Bond definition (see above) was the best one to adopt. He described World Ship concepts such as those presented in Arthur C. Clarke’s novel Rendezvous with Rama. He said it was important that every few decades we discuss the margins of World Ship definitions, looking for show-stoppers to ensure they are not neglected. The evolution of the World Ship concept was described and three reasons for their construction given: (1) saving the human race, (2) inevitable expansion of living space, and (3) actively driven colonization plans. Webb made the important point that humans began to envisage the concept of a World Ship as soon as our knowledge of the physical universe allowed us to do so.

Webb next considered the question of who would sponsor a World Ship, and why they would do it. He said that any society interested in building a World Ship will begin to do so when they have enough materials, energy, information and motivation for doing so. He added: “once the solar system economy is big enough, only the last [motivation] will present a problem for World Ship fulfilment, since ‘starship building man’ is in a very small minority now and may always be”. Threats to long-term human spaceflight prospects were defined to be collision risks, gravity, radiation risks, infections and social disharmony. He considered the factors that make humans what they are, and defined us as Genes (G), Culture (C) and Ideology (I) which are the hardware, operating system and program respectively. He said that all three of these elements would be of equal importance in attaining a human success in World Ship building, and hence our survival and expansion into the galaxy.

An important point made by Webb was that it had been found that approximately 1% of every nation on earth was made up of so-called psychologically difficult types, meaning manic depressives or those suffering from mental disease. This remarkable constancy, it was claimed, may have contributed to human cultural and ideological advances. In discussions, Kelvin Long pointed to the Arthur C. Clarke story The City & the Stars, which had a small instability element to the population. Webb argued that the government of a World Ship was very important in order to maintain stability. He referred to the Aristotelian organization of states in order of decreased stability as Tyranny (monarchy or totalitarian), Oligarchy (aristocracy or elitist) and Democracy (polity or republican). Those sponsoring a World Ship would be natural expansionists—ark builders—and the pressures to do so would be government funded programs, private funded, or internal pressures such as victimization or resource depletion. Finally, he said that given a big enough economy, World Ships would be inevitable, and each ship may be very different, based on different beliefs and ideologies. Darwinian natural selection would ensure that only the fittest would reach the destination stars. The others would simply not make it there. He ended with a cautionary note relating to the Fermi Paradox which may become more topical by the time that a World Ship is built and said that if alien World Ships exist, they may not be sympathetic to us.

Estimating a Launch Date

Stephen Ashworth gave a presentation on “A Development Roadmap for the World Ships.” The speaker raised the possibility that we may become extinct before we have a chance to build a World Ship. Ashworth thought that the construction of free-orbiting space colonies would be prototypes for World Ship living quarters. He discussed current propulsion technology such as that used by the DAWN spacecraft travelling at around 30 km/s, and speculated on future propulsion systems.

Ashworth strongly disagreed with the picture painted by some of an ‘Independence Day’ scenario where colonies hop from one world to the next to extract vital resources. He displayed graphs illustrating the sum of journey and exploration time against habitability time (the duration upon which we could inhabit artificial space colonies for a continuing duration). The point at which the figures cross over was said to be an estimate of the time at which we could likely launch the first World Ship. 2357 was estimated initially assuming progress in both life support and propulsion. However, if progress in propulsion is more rapid, Ashworth believes the first World Ship launch date could be brought forward to a much earlier date. If life support technologies progress but propulsion does not, then the launch date would be pushed back to around 2450. Alternatively, if progress in life support technologies and propulsion declined then the two curves may never cross each other, meaning we may never launch a World Ship.

Ashworth concluded by saying that much attention was being placed on finding an Earth-analogue planet, and although he thought this was a worthwhile pursuit of scientific study and recreation, he did not think it was the object of resource extraction or colonisation. In all likelihood, he said, humans would prefer to live in artificial orbiting space colonies rather than living on another planet. This view was not shared by all present. In particular Martyn Fogg (of terraforming fame) said that he would like to see the habitable planets and this would be a reason for making the journey. Ashworth ended by saying that World Ships would be a logical end point to the colonisation of the solar system — they are inevitable.

The Economics of Interstellar Growth

Finally, Frederik Ceyssens gave a presentation titled “On the Financing of World Ships & Other Gigascale Space Projects.” His co-authors were Maarten Driesen and Kristof Wouters. Ceyssens discussed the new age of discovery, in which astronomers are finding hundreds of exoplanets constantly. He argued that there will be more interest in exploring and settling on another habitable world. Such settlements may have greater potential for grand scale colonisation than a colony in our own solar system and also provide long-term survival and knowledge-generation benefits. The question for him was whether this interest is sufficiently strong to attract funding.

Ceyssens defined some of the challenges facing current space exploration, namely low-cost access to space, very high specific impulse propulsion, high reliability and lifetime for equipment, and creation of life support systems. His conclusion was that a World Ship would be an ultra long-term project and at high cost. He said that a World Ship would be equivalent to a ‘beefed up’ megaproject such as Project Apollo, megaprojects being defined as involving a steep threshold unsurpassable by normal economic or scientific development. As well as Project Apollo ($100bn) he discussed other megaprojects including the Manhattan Project ($22bn), ITER ($20bn) and the construction of either an interstellar probe ($1,000bn) or a World Ship ($10,000bn). He considered projections for World Ship investments assuming set annual growth figures.

Ceyssens’ proposal for achieving the eventual launch of a World Ship was the formation of a ‘Fourth Millennium Fund’ which he argued would be transparent, have global outreach, be lean with a low cost structure and have a single well defined goal, such as finding a second home for humanity. He was looking for people to invest today and to commit to such long term investments to ensure that a World Ship could be built in the future, once we could afford it. It is worth noting that Alan Bond made a comment that, in his opinion, money as we know it in the future will not be the economic system by which things are constructed and resources are allocated.

A Fallback Plan for Earth

During the subsequent discussions many competing views emerged from the attendees relating to World Ships. One of these was the view that before any World Ship would depart it would first identify a habitable planet to head towards. However, several attendees thought that the advanced crew (so called Starship Man) would no longer be interested in settling another planet but would instead be content to live in artificial structures in orbit.

The question of when such a mission would be launched was also debated. Some saw it as an inevitable gradual process of solar system colonisation placing it many centuries into the future, whilst others thought that circumstances on Earth (e.g. catastrophe, war, famine) may give rise to the construction and launch of such a mission much earlier than people think. This would also determine the stability of the crew aboard the World Ship. A mission planned centuries in advance with great care would have a well organised community on board paying attention to population control, policing and resource usage. But a World Ship constructed in a hurry may have less detail in the planning, with the result that only a dictatorial style rule on board the vessel would be capable of maintaining social stability. These sociological factors would likely have a significant impact on the success or failure of such a mission.

As we consider the future prospects of mankind on Earth and in space, it is important that we keep our options open. From the perspective of today’s society, with a large population, poor resource distribution, and in financial crisis, the prospects for building a World Ship some day seem at first sight to be pure science fiction. However, there is nothing in the laws of physics or in the many text books on engineering that suggest a World Ship is impossible to build. As indicated by Alan Bond during the discussions, a future society, perhaps in a better position than we are in today and with a more positive outlook on the Universe, may look upon such an enterprise as an equivalent undertaking to Project Apollo in the 1960s. Given the potential threats — internal and external — that humanity may face in the future, it is important we keep our options open and continue to strive for expansion into space. Designing World Ships is a lot of fun in the practice of extreme aerospace engineering, but it is also a possible fall-back plan should the future turn out to be bleak for humanity on Earth.

Image: Kelvin Long (left) and Alan Bond at the conference.

On a final note, we have to accept that if humans can conceive of a World Ship, then so could an extraterrestrial and they may be out there now star hopping, perhaps on their way here. Alan Bond pointed out that a nuclear pulse engine would be detectable from large interstellar distances and would appear to be a double-ping milli-second pulsar running down on the timescale of decades as it moves away from us. He said that our machines will colonize the stars before us, and so might the machines of another race. Perhaps we should be more concerned if the starships were coming towards us.

It is worth ending this article on a cautionary note from Arthur C. Clarke: “I can never look now at the Milky Way without wondering from which of those banked clouds of stars the emissaries are coming.”

The two original papers referenced in this article by Anthony Martin and Alan Bond are “World Ships – Concept, Cause, Cost, Construction and Colonisation” and “World Ships – An Assessment of the Engineering Feasibility,” both published in JBIS, volume 37, number 8, June 1984. Kelvin Long has also published a separate conference report on the Project Icarus site.


Comments on this entry are closed.

  • Greg August 31, 2011, 9:38

    The issue with World ships is, do we force our children to endure this trip? specially the ones who will be born on route? Some of them may not want to live in such a small “world” only to know they will die between star systems.

  • Alex Tolley August 31, 2011, 9:48

    We really are like neolithic people discussing how we might build a cathedral, based on our knowledge of knapping stones, piling up some rocks, and expecting that people will still have some sort of religious ceremonies in the future that would require such a structure.

    One peripheral issue I would raise is financing. It has been mooted on this blog before that some sort of [private] foundation should be created and that investments started now would become large enough to finance part of the operation. In the report about, it was suggested a starship might require $10tn and be launched in a few hundred years. I would suggest that such a large sum, even in the future, would probably be looted long before it could be used. We’re probably talking about a world that has a very different set of great nations and ideologies. Planning, by even the most dedicated of groups, for a target centuries in the future given the pace of change we see today strikes me as unrealistic.

    One other consideration that doesn’t seem to have been raised except tangentially in terms of relative starship velocity. Suppose group A decides on building the worldship. Group B however thinks that very fast, self replicating robotic devices are the way to go. Group A’s ship might arrive, only to find group B’s robots now not only claim the target they have populated, but are actively hostile to the worldship. The volume of space with claimed worlds might well outpace any slow worldship probable targets.

  • Tulse August 31, 2011, 9:54

    I think the grand speculative nature of world ships is wonderful, but I am deeply dubious of their utility. In terms of offering another home for humanity, bases on Mars, the moon, asteroids, and free floating habitats offer a much more practical alternative, with far less cost and risk, and would mitigate the danger of a single home for humanity just as well (there are very few near-term calamities that would be solar-system wide).

    And I am also unclear what problems there are to solve with developing a practical world ship that wouldn’t be likely addressed in the nearer term by developing independent habitats and high-speed propulsion for robot probes. In other words, focussing on world ship development seems premature and somewhat inefficient to me, since we’re very likely to create free-floating habitats and high-speed propulsion sooner for other reasons.

  • Sith Master Sean August 31, 2011, 12:38

    I question those who think that an interstellar World Ship could happen as a response to war, catastrophe or famine. Where are the resources going to come from to build such a thing in a time of global crisis? It’s particularly amusing since this conference was held in the same city which burned in senseless riots days before. Now imagine what a real crisis would be like!

    This is my problem with this whole issue: it strikes me as pure escapism, which I’m all for, but we might as well just be discussing science fiction novels. The real problem humanity faces in getting to the stars is ourselves; I’m quite skeptical that our current species is up to the task. If you want a grand, futuristic project that has a better chance of success, I would suggest devoting yourself to a “Superman Project” to improve humanity technologically and genetically. The creation of “homo superior” would enhance human and transhuman potential in every area, and to my mind is the proper great project of our technological civilization. I therefore propose a new motto: “Ad Homo Superior, Ad Astra.”

  • kzb August 31, 2011, 13:15

    The political barriers to “homo superior” are orders of magnitude larger than producing a starship !

  • Bounty August 31, 2011, 15:13

    I’m pretty sure worldships will just be free floating habitats with propulsion. (Well and a lot of fuel.)

    At this point we don’t know if self replicating robots, bio-immortality or perfected life suspension will come first. In the mean time, we know the grow, replicate then die cycle works, so that is why people are working on that path for now.

    It’s biggest drawback is the added weight, but we already know how it works. We can technically draw up designs now, unlike those other methods. Well I guess we could do the robot thing, but you would lose most of the adaptability of a human. If something doesn’t go right, there is no plan c when you’re a robot 2 light years away.

    Maybe it depends on if we have human colonies on the moon/mars or robot colonies on the moon/mars first. That’s going to be the learning ground for this sort of thing.

  • Frederik August 31, 2011, 16:26

    About the financing aspect, I’m still convinced that it makes sense to try to build up a fund for for bringing humanity to the stars (not necessarily though the use of world ships, probably the most expensive method of interstellar colonization of all):
    – It will have to be a strange kind of charity. No one alive today or in the future will get enough tangible benefit from an interstellar expedition to justify paying more than a symbolic share of the cost. If only the universe had given us better laws of physics or closer neighbors…
    – The current capitalist economic system is in place since the 1600s. More and more vested interests depend on its continuation.
    -The fund of the Noble Foundation is operational for over 110 years, having a return of 1.7% above inflation despite the crash of the 1930s, two world wars and countless recessions.
    -At that return, if an amount equal in worth to one tenth of the yearly budget of the five main governmental space agencies combines would have been put in a fund yearly since 1900, it would contain over 1 trillion now, enough to fund a serious program leading to a first unmanned interstellar probe.

    There are counterarguments: our current civilization must become sustainable this century or it will collapse, AI might replace us despite the opposition to it that will definitely arise, the world economy will grow exponentially forever so why bother now (yeah right) and so on. But, if humanity will just muddle along, saving up might be the way. And it will probably be a few space enthusiasts crazy enough to start the idea up, just like a few people who cared enough started the WWF, Sea Shepherd… And it will take a lot more people and support to make it work as well as those organizations (which are actually a network of organizations branched out worldwide), of course…

    I’ll leave it at this, much more can soon be found in the papers in the coming issue of the journal of the BIS and online.

  • Don Elder August 31, 2011, 17:56

    Somewhat depressing reading an article by such long term forward thinking folks, while on the other side of my screen I see the headline that the space station may come crashing down because some idiot government and NASA folks can’t think more than 3 days ahead.

  • Astronist August 31, 2011, 18:49

    @ Greg: I don’t think anyone is talking about anybody forcing their children to endure an interstellar voyage. Rather the concept is more of such voyages emerging naturally from extensive Solar System colonisation. The world of a worldship may be small by our standards, but it will be a perfectly normal way of life for most of our descendants. Especially if a number of worldships travel in convoy.

    @ Tulse: Mars and the asteroids are for the next few centuries, starships for later on, when humanity (or post-humanity) is well adapted to extraterrestrial life. Just as it was not Europe which launched the Apollo flights, but a European colony, so it could well not be Earth which masterminds the first interstellar flights, but Mars, or Ceres, or Callisto, or a consortium of some of these.

    This project is a political one as much as an engineering one: a statement of intent for the continuing of the paradigm of growth and progress and an expanded future for humanity (the opposite of the “small is beautiful” Marxist/environmentalist/anti-capitalist movement).

    Thanks again to Kelvin for all his work and enthusiasm organising this symposium and bringing it to fruition.

    Oxford, UK

  • bigdan201 August 31, 2011, 19:06

    To reiterate some of what I said before:

    We’ll have to focus on the exoplanet search and potential interstellar destinations before launching any worldships. Until we have another solar system rich in resources and/or an exo-earth, it just won’t be feasible to cross the parsecs.

    Solar system colonization will develop long before, unless a very interesting target is found within ~40 light years or so, the closer the better. Within 10 would be ideal, while 100+ would be a real stretch.

    Some of the worldship population will disembark at the exo-earth, but most likely not all of them will.

    I will emphasize that space colonization must be our destiny. I’m not old enough to remember the cold war, but there was a real possibility of global nuclear destruction, a severe setback to civilization. There was a time when the world was separate enough to insure survival. The fall of Ancient Rome did not have too much impact on ancient China. But we’re now in each others backyards, and the world is no longer large enough. Space colonization will insure survival, solve the environmental conflict, and counteract homogenization.

  • kelvin August 31, 2011, 19:41

    Dear all,
    interesting comments so far. Here are my replies.
    Greg, you make an excellent point. Imagine coming of age and discovering that your world was really in between worlds. Some may find this exciting, for others it would be routine as its all they have ever known, but others may find this overwhelming, to never walk on the green river banks of the amazon. Then again, as Stephen Ashworth pointed out to me recently, they will have their hollow decks.

    Alex, I tend to agree with you about saving money over many centuries. I doubt it will last that long. We need more permanent ‘things’ to survive into the future. Works of art perhaps, land?? I don’t think building a world ship will be as expensive as people say anyway. Who knows what nano technology will be able to do in several centuries from now. Alternatively, perhaps it will be constructed on protocell technology, the ship will simply grow itself.
    Regarding your Group A/Group B scenario, this is a version of the “wait to launch” postulate which Marc Millis frequently discusses, including on this CD forum. I will add that you have possibly described a neat science fiction story there – budding writers anyone?

    Tulse, its important to have these sorts of discussions occasionally so that the subject slowly continues on as a research field in the background. I would certainly say that world ships are not anyones ‘focus’ right now, its just interesting to discuss them. Your views on alternative habitats to a world ship reflect the divergent views expressed at the conference. Some were clear that they would want to colonise a planet, moon or free floating planet, and this was a reason for going. But others were adamant that living in large space based artificial structures would be more than sufficient if not preferable. Perhaps we need all of these to satisfy a diverse human need. Perhaps, many world ships will one day be launched and each will do their own thing. i think I would be really interesting to see how each habitat develops, planetary or artificial, and what social systems function successfully.

    Sith Master Sean, I asked this same question at the conference when ‘poverty’ was identified as a driver for a world ships. I saw this as a potential contradiction as you have highlighted. But, perhaps one group of philanthropists of the future would see it as a way to escape the impending doom of a bleak existence before them as the world began to crumble under its own human mismanagement. I like your suggestion of alternative projects, argubly this is going on now with the development of stem cells, gene therapy, DNA mapping, perhaps we will get there. However, note to self: inject superhuman spider powers before tea.

    Kzb, have you seen X-Men?

    Frederik, you make your points well and I think they speak for themself. Its important we keep our visionary nature and as a specied don’t just focus on short-term gains.

    Don Elder, shucks! they live in the real world of politics. Those of us on Centauri Dreams live in a wonderful dream world where everything is possible if we try hard enough. Somewhere in between lies a good balance between the dream and the practical, I still think that balance is indicative of stupendous achievements before us. Be optimistic, and you may help to bring about a self-fulfilling prophesy on earth and in space.


  • mike August 31, 2011, 21:06

    i am glad to see the whole breath and depth of the impacts of a 100 yss being bantered about.

    i want in on it. i want a good paying job with good pension and good health insurance. otherwise i say we ditch it now, DARPA be damned.
    stone knives and bear skins V2.0! OOO-OOO! AHH-AHH! planet of the apes.


    i think that globe trotting boffins are in for a big shock when joe six pack sez NO! to the whole adventure. unless us shlubs (the outcasts) are cut in for a piece of the action, the whole ball of wax is going up in flames.

    so…how about the russian supply vehicle to the ISS crashed and now the ISS is to be mothballed. all run by scientists ans engineers. you got my vote of confidence, NOT!

    i’m all for it. i want the 100 yss to happen, just not the way TPTB want it to go down.

    should a star ship have weapons? what does DARPA say to that?

  • stephen August 31, 2011, 22:59

    You discuss worldships of enormous mass; could we just use asteroids?
    A group could colonize the interior of Ceres or Vesta, using the mass of the asteroid as source material. Part of the mass would become the engine to propel the worldship. It would be very slow, but is this doable? Thanks.

  • estorm September 1, 2011, 2:18

    Sith Master Sean pointed out a very real dilema that must be faced dead in the face. The idea that Earth can provide a long term nest-egg long enough to keep exponential growth in the next ten decades is problematic without optimal forms of technological innovation. These innovations keep coming in the form of energy and information, but sustainable development might be a real issue here. We need to wrap our arms around a vivid exponential growth model that some how defies gravity by not impeding as much on the complex ecological systems on Earth that provide life. Perhaps the advancements in sensory, communication, and processing power (neurosynaptic chips) can provide answers to how we can maintain a stable planet, and thereby increase our chances of reaching the stars. In fact, I suspect there might be a lot of overlap in the technologies that are able to provide the high fidelity measurements in our global environment, and the high fidelity measurements that will be required to maintain the climate of an Earth Ship, as well as many other functions. I’m beginning to take this longer than it needs to go, but this is only one aspect of how we need to recast our focus on problems here at Earth. The dilema makes me no less excited about the prospect of solving these problems and going to the stars.

  • Astronist September 1, 2011, 6:19

    @bigdan201: I am informed by an astronomer friend that it is likely that almost all main-sequence stars are accompanied by asteroidal rubble. If a space-based rather than planetary civilisation were to arise, this would therefore make almost all main-sequence stars targets of colonisation by such a species, regardless of whether Earth-like planets were present or not. Or to put it the other way round, the Galaxy will be colonised by space-based species much faster than planetary ones because of the greater asteroidal resource base as opposed to terrestrial planet base.

    @kelvin: my point is not that people would prefer a planet to a space colony or vice versa. It is simply the logical argument that (a) the potential ecological niche for a space-based species is about 1000 times larger than that for a planet-based one, (b) colonising planets leads naturally (thru cycler-style transports) to development of space colonies, and (c) any species that makes the jump to a purely space-based lifestyle (which may or may not be H. sapiens or a daughter species of H. sapiens) will grow to predominate the life of its planetary system of origin and also that of the Galaxy in general. (I leave intergalactic travel for the next generation of visionaries!)

  • Max September 1, 2011, 8:29

    I don’t think world ships will ever be built, unless they reach their destination in significantly less than a human lifetime. Nobody in his right mind is going to voluntarily imprison himself in a cylinder in the vast emptiness of interstellar space for the rest of his life, just so that his great great grandchildren may arrive in another star system.

    If crewed interstellar travel becomes a reality, it will be in spacecraft which will be going at a significant fraction of light speed (unless you find a way to put humans into hibernation for decades to centuries).

    What trip times are deemed acceptable depends on a) the length of a human lifetime, (b) the size of the vessel and (c) the velocity. If a) and b) are high c) may be somewhat lower.

    If by 2200 humans live an average of 120 years and hibernation is not possible, I’d say one-way trip times shouldn’t exceed 10 to 20 years, which calls for speeds of 40 to 70% the speed of light, if the nearest stars are the destination. Which technologies would be up to the task? Only beam-pushed sails and pure matter-antimatter annihilation.

  • Ronald September 1, 2011, 9:28

    With regard to distance to the nearest habitable planet the following;

    The number of habitable planets in our galaxy has been estimated by a few studies (and my own draft guestimate) to be in the range of 50 to 200 million, of which by far are assumed to be in the galactic disc, and not too close to the core.

    If we take a radius of 50,000 ly for the galactic disc and an average thickness of 3000 ly, for 100 million ‘habstars’ evenly spread within it, the mean distance between two habstars would be 38 ly. If we double the number of habstars to 200 million, the mean distance the becomes 30 ly. And if we halve the number of habstars to 50 million, the mean distance the becomes 48 ly.
    So, I would say, anywhere between roughly 30 and 50 ly.

    If Alph Cen B had the nearest habitable planet, it would be a real bonus.
    If it were 61 Virginis (28 ly), Alpha Mensae (33 ly) or 18 Scorpii (45 ly), it would be realistic.
    If it were HD 101364 (the closest solar twin found so far) at 217 ly, it would be disappointing.

  • Ronald September 1, 2011, 9:47

    Oops, I think I should have doubled those estimated distances. That is, I calculated the radius of the (spherical) volume of space that surrounds each habstar, on average.
    So, for the distance between two habstars I should have taken twice that radius, i.e. ‘anywhere between roughly 60 and 100 ly’. However, for our part of the galactic disc it may be a bit lower, indeed between 30 and 50 ly.

  • ljk September 1, 2011, 12:08

    I must admit I never thought I would see in my lifetime anyone or any group outside of a science fiction story conduct some serious, organized thought on the idea of a multigenerational interstellar worldship. Or an automated interstellar probe for that matter. Now we have The Ultimate Project and this worldship conference, along with Icarus. I also hope someone will be reviving the Orion concept real soon and even looking more into antimatter propulsion. While I obviously would be even happier if we got off the drawing board and starting putting some metal together, this is a heart-warming (or is that brain-warming?) start.

    All this is a nice sign of hope to show people that the human-made problems on this little ball of rock are not as bad as what our ancestors endured in the past and we are still here. Anyone who grew up during the Depression, or World War 2, or even the Cold War can tell you that there was a lot of hope and optimism for the future despite those issues, which could have literally brought our civilization and species to its knees, or even extinction. Even rocket societies popped up all over the globe during the 1930s of all times, leading to our Space Age just two decades later.

    Now about these persistent concerns over people being stuck in confined spaces for generations and the necessity of an Earthlike exoworld to give such a space mission a purpose and goal: Unless someone here has a surprise for us, I am willing to bet that the vast majority of humans and their ancestors have spent their entire lives confined to the surface of a sphere a mere 8,000 miles across (one million Earths could fit inside the Sun, a dwarf star in its own right, to give you an idea how tiny our planet is in comparison to the rest of the Cosmos).

    Most of the residents of this “spaceship” have rarely ever left the vicinity of their birth village, even though global transportation is now readily available. A lot have also never even looked up at the sky or know much about it. In fact, until a matter of centuries ago, most humans were unaware they were on a ball of rock going in an endless circle about the Sun. These same humans also have had to make up a purpose for their reason of being here or live in the delusion of a purpose and goal on this ship.

    So how much should we worry about people who will be “confined” to a ship that will cater to all their needs, where they will have to be a tight-knit community working together towards a real goal? And don’t forget, virtual reality will probably be at a level where they can go off to all sorts of places without the usual expense and danger. Already we are seeing a generation that happily spends hours every day on the Internet or glued to some hand-held device with plugs in their ears.

    Now as for this need to find another Earth in order to make an interstellar journey viable, I will briefly repeat what I have said elsewhere on Centauri Dreams: Not only might it be hard to find an alien planet where humans and other terrestrial organisms could take root without a lot of modifications, it is foolish to assume that a planet friendly to life would not already be occupied. Even if the native residents are no smarter than, say, cows, do we have the right to push them aside or worse? Better hope someone else out there with similar ambitions would think twice before moving in to Earth.

    And would our travelers really need or want to land on a dirty, dangerous planet after spending ages in their clean spaceships? Exploration and supply runs I can see happening, but living there is another matter. Oh of course some may opt to do this, but the ship itself will carry on voyaging through the galaxy. Hey, if you had the ability to explore the Milky Way, would you just want to go to one planet and stay there?

    I still think our first and ultimately best interstellar explorers will be the Artilects that will be the brains with the ships as their bodies of the whole missions. I also do not see a lot of consideration as to how and how much humans might change themselves in the next few centuries, though we are getting some indications now.

    I think it is safe to say that if our society does not stagnate or degenerate, humans will be trying just about everything available to modify themselves to be better physically and mentally, so they may be even better equipped to handle a multigenerational space journey than many seem to think now, basing their attitudes on current humanity.

    So let us at least try to get outside some of our paradigms based solely on our experiences stuck on this one little rock to better imagine how a more sophisticated humanity might handle interstellar travel and colonization.

  • Rob Henry September 1, 2011, 17:16

    A frequent theme here is that confinement to a worldship may induce the stress of imprisonment into many of the occupants that were born into it, yet I can’t help thinking about the reverse possibility.

    Due to its massive capital cost per person and lack of production onboard, life there should resemble a fabulously wealthy egalitarian paradise. The stress endured might be due to the sure knowledge that the majority of their ancestors, and descendants, were, and would be, denied this privilege.

  • ljk September 1, 2011, 21:31

    Or, Rob, those who are on the journey but will not live to see the destination, which does not have to be one place, can know that they will have children who will have children and on and on who will have a nearly guaranteed future and a better life.

  • Matt Metcalf September 2, 2011, 10:22

    @ljk, you said “if our society does not stagnate or degenerate, humans will be trying just about everything available to modify themselves to be better physically and mentally”. I’m sorry, but that’s hilarious. Of course they won’t do that. Oh, some will. But the vast majority won’t. Do you know how I know? Because they have the ability to improve themselves today, both physically (through exercise) and mentally (through education). And most people (at least in the U.S.) would prefer to sit on their fat asses watching the latest reality TV excrement than improve themselves or the world around them. We’ve become too complacent.

    @Rob Henry (and ljk), you seem to think the people on the worldship wouldn’t have anything to do. I think that’s probably not true. How many of the things in your home are centuries old, or even decades? The ship is going to have to have some ability to repair stuff that breaks (especially critical systems like power, thrust, and life support). But also it’s going to have to make new systems to replace old ones that just wear out. Obviously, a nanotech fabrication system that can create anything you need from raw molecules would be great, but failing that, it’s going to need manufacturing facilities. And people are going to have to work.

    But beyond that, people should work, even when there is nothing that needs to be replaced. The ship could (and should, for various reasons) be stuffed with scientists and engineers. And as long as the ship can communicate with Earth, those people can continue to do research and development work. As employees of the corporation or foundation or whatever built and launched the ship, any intellectual property they create would be the property of the organization (besides, what are they going to do with Earth money?), and the organization could then use any proceeds to help defray some of the costs of building the ship. Or to buy the latest entertainment products (movies, music, books, video games, etc.) to be beamed back to the ship. Or to license patents for improved systems (better nuclear reactors for improved power generation, better thrusters to get to the destination more quickly, more efficient and longer-lasting life support systems, the latest generation of Xbox, etc.) that could be sent back to the manufacturing facilities on the ship so that it can be upgraded en route to its destination.

    As for staying on board versus disembarking at the destination, I think you’ll have some of both, and that’s probably fine (and preferred). If we can’t find some really cheap, reliable, safe way of getting into and out of a gravity well, we’re headed for social stratification into two general classes of civilization anyway: planet-bound and space-bound. As to which I would choose… well, it would depend a lot on what the planet looked like and how long it was going to take to get to the next one. If I had been born on the ship (a sixth-generation crew member, say) and arrived at a habitable planet with fresh air and open sky, I might be hard pressed to get back on the ship so that six generations later one of my descendents could make the same decision about another world.

  • Bill Thayer September 2, 2011, 17:23

    I’m with Max: the world-ship would best fly if it got where it was going in 30‑40 years. A way around that would be to send it off under the control of machines, with a birthing arrangement toward the end; but that’s even more radical than some of the other proposals, and involving all kinds of other problems.

    I find no problem on the other hand with children being born on the flight who might not have wanted to be born there; it’s not like children who for millennia have been born on Earth have had any choice in the matter, and we usually don’t fault the parents for depriving them of any liberty.

  • ljk September 3, 2011, 1:54

    And what I find hilarious, Matt, is that you assume I was talking about people doing basic exercise and education when it comes to the future and dwelling aboard a worldship. No, I am thinking that as technology advances, people will create and use certain technologies to modify their bodies and minds in ways much more sophisticated and radical than what most people today envision.

    Already we see people trying to look younger with multiple plastic surgeries and enhance their physical prowess with various medicines. How much longer will it be before we develop techniques to implant large amounts of information directly into our brain and reshape our bodies to not only change our appearance but make us much stronger and faster?

    Of course what I really see happening is that our next step in evolution goes past these things after a few centuries right to the development of Artilects which far surpass the limits of our human selves. They will be far more capable of exploring the stars and dealing with alien intelligences.

    And I do not believe I said that humans would have nothing to do on a worldship. I think they will have plenty to do and may enhance their experience with virtual reality and other advances of the near future.

    Though part of me also see a human crewed starship as a vision of an earlier era that did not forsee all the technological advances we can and will do. Of course some groups may attempt to launch their human members into the galaxy without waiting for fancy advances, so who knows?

  • amphiox September 3, 2011, 2:34

    @Tulse, keep in mind that a World Ship is basically just a free-floating habitat made a little bit bigger, more robust, and with an engine and fuel tank added onto it. In other words, once you have the technical capability to make free floating habitats, turning one of them into a World Ship is just a matter of some retro-fitting.

    And if the Solar System ultimately fills up one day with free-floating habitats, it seems likely that some group of people, somewhere, will choose to turn one of their habitats into a World Ship and go off somewhere. Possibly many such groups at once, even.

    The other thing to consider is that if a human presence in the Solar System in free floating, or perhaps self-propelled habitats extends out into the Oort Cloud (habitats might choose to use Oort Cloud bodies as sources for resources), the distance between the outer edge of the Solar System’s Oort Cloud, and the equivalent cloud around Alpha Centauri (where there are more resources) isn’t very far, relatively speaking. And if time is no longer an issue with World Ship journeys planned to take generations, then neither is a straight trajectory. We might instead see a star-hopping strategy, where the ship moves between the outer Oort Clouds of neighboring stars, stopping to harvest resources/manufacture fuel in these regions, before moving on.

    And this scenario brings up one further potential possibility – that such habitats/world ships could “reproduce” themselves, by using local resources at one of their stop-overs to manufacture a copy of itself, into which a portion of its population could move, and then the two ships could separate and travel in different directions. One ship could remain and explore the local star system, for example, while the second could continue on to the original destination. One ship could even choose to return to the Solar System. This would provide a potential outlet for individuals of future generations who no longer wish to participate in the original mission.

  • amphiox September 3, 2011, 2:42

    The people on a World Ship will for all intents and purposes BE a human space colony. Particularly if it is one of the bigger World Ship concepts intended to house several thousand individuals. The only difference is their colony is moving. They are going to have and develop their own social structure, culture, industry, and politics. Work will absolutely not be a problem for the colonists. In addition to crewing and maintaining the ship itself, they are going to have the whole gamut of human activity – art, science, entertainment, service, etc.

    If anything, a greater danger might be breakdown of political stability in the colony/World Ship, leading to factionalization and self-destructive conflicts between the crew as the generations add up.

  • Michael Simmons September 5, 2011, 2:15

    I look forward to the publishing of these papers.

    Are people on these worldships going to be as protected from radiation as people on earth?
    I can see us colonise the solar system, sending out a number of worldships, and then having the whole lot wiped out by a nearish supernova or GRB.

    The faster you go the more shielding you need to protect yourself against micrometeorites and cosmic radiation.

  • Tulse September 7, 2011, 16:39

    if the Solar System ultimately fills up one day with free-floating habitats

    “Fills up”? Space is really, really big, and the “habitable zone” around the Sun is very very large.

    In addition, by abandoning the solar system, a habitat is also abandoning a huge source of free fusion energy, the Sun. An interstellar habitat will require far more energy (because it doesn’t get free heat and light), and will at the same time not have access to any external energy source (either solar or external fuel). That’s a huge limitation. Deep space is a far more hostile environment than hanging around a nice warm sun.

  • ljk September 8, 2011, 9:55

    That wild rebel astronomer Fred Zwicky once thought about using the entire Sol system as a “starship” for getting around the galaxy. We would just drop certain elements into our star to get it to react and act as a “rocket” to slowly but surely push us through space to another system.

    We would not have to worry about living in cramped quarters or wondering where our resources would come from – we would just take home with us.

    So, have astronomers detected any unusually speedy star systems moving about the Milky Way lately?

  • Interstellar Bill September 9, 2011, 20:42

    I wish more science fiction authors would read these comments for story-settings, instead of wasting time on FTL and the obsolete meme of ubiquitous colonizable planets, let alone widespread ETs. Puhleez!

    I was there in the 60’s as this myth took hold,
    with Star Trek and Star Wars mere froth on the idea’s widespread adherence.

    As a minority meme but a scholarly enterprise, the entire space-industrialization scenario was been well studied over the past decades, but somebody please tell Hollywood.

    Oops! They can’t even show constellation-backgrounds, just paint splats.
    Such clods are incapable of wanting to depict the actual future,
    just their childish space-opera fantasies.
    At least fantasies depicting Tolkien-like medieval worlds,
    as well as the paranormal, witchcraft, werewolfs, mages, etc.
    are unabashedly contra-reality.

    The FTL fantasizers need to put away their comic-books
    and apply themselves to interstellar studies,
    starting with this blog.


    Laser Sail!!!!!!!!!

  • kelvin September 10, 2011, 17:59

    Hi all, catching up with the responses so far.

    Stephen, the idea of using an asteroid for a world ship was the basis of the original Bernal sphere in 1929. It would be built out of either an asteroid or a small moon, although he claimed it would move at the speed of light (mmm!). He did work out all of the main details for a world ship however, including the atmosphere. Using asteroids may indeed be viable one day, although it would require the technology of large scale space engineering.

    Max, if a world ship takes only a few decades to get to its destination, then why use a world ship anyway when there are easier, more efficient methods?

    Regarding propulsion by 2020, I would vote for two potential dark horses (1) Bussard ramjets, I think the problems may be solved in the future (2) some exotic propulsion scheme such as vacuum engineering. My point is, propellantless solutions will open up the wider star network.

    Ronald, these are interesting estimates of 30 – 50 ly and 60 – 100 ly. These are not unreasonable estimates. I have seen estimates vary between about 30 ly and 180 ly in recent years for the nearest habitable planet. Personally I am mainly interested in any stars within ~15 light years, possibly as high as ~20 ly. But realistically, epsilon eridani at 10.7 ly is likely at the outer practical bounds of what we could reach in a human lifetime, one day, even if we have very advanced propulsion. But this is very interesting because correct me if I am wrong but haven’t astronomers now identified two dust belts, a 1.5Jupiter mass planet and a 30Earth mass planet in this system. My money will always be on the Centauri A/B and Proxima Centauri system. Its closer, has three spectral types, two of which are similar in mass to our Sun (+/-10%), slightly older system which could be interesting from a dynamical evolution perspective. I hold out hope for a profound discovery around this star system in the near future. Time will tell.

    Ljk, note that such serious thought has been a slow process over many decades, culminating in the 1984 JBIS papers in my view where World ships were properly considered from an engineering and physics perspective. The papers are well worth a read. Regarding your other comments, hope and an optimistic vision for the future is what gets us through the dark days. For the British, the answer is always tea of course.

    Mat Metcalf. Interesting comments overall. I like your point that many people do not improve themselves physically (through exercise) or mentally (through education) today given a choice; although I appreciate the distinction later made by ljk. But I think your point is that it is the same mindset that chooses or chooses not to accept these new technologies. But I think like much of history these mental and physical technologies will be developed by the pioneers, a minority of the species who do push the species forward. As a consequence these technologies will be offered to the wider species (even if for a fee) and so the whole species will eventually develop and benefit, lazy or not.

    Amphinox, we are already on a ‘moving’ world ship – it’s called EARTH. But if how our cultures(s) behave on this world is any indication we are not yet ready. We are still experimenting with the appropriate social models. Its disappointing that we can’t even do experiments like Biosphere 2 correctly, a good idea but from what I have heard could have been managed better. You also referred to a breakdown of political stability on a world ship. We did discuss this a bit at the symposium and indeed one of the speakers (who couldn’t make it) was going to discuss the policing of world ships. It’s an interesting debate in itself.

    As a final comment (for those of you that can), over here in England we have the Eden project in Cornwall. It’s a wonderful place to explore. When you are walking around those huge domes you can’t help but imagine you are exploring the gardens of a world ship. They also remind me of that neat little science fiction movie ‘Silent Running’. Imagination is always a great escape.

  • ljk September 12, 2011, 10:15

    Kelvin said:

    “Ljk, note that such serious thought has been a slow process over many decades, culminating in the 1984 JBIS papers in my view where World ships were properly considered from an engineering and physics perspective. The papers are well worth a read. Regarding your other comments, hope and an optimistic vision for the future is what gets us through the dark days. For the British, the answer is always tea of course.”

    Will the BIS ever put these and other papers by them online?

    Regarding a cup of tea as the answer to our future issues, didn’t Douglas Adams come up with tea as one of the ingredients of the Improbability Drive in The Hitch-Hikers Guide to the Galaxy? May well be worth looking into, having one of your food staples and drive fuels in one.

  • Rob Henry September 13, 2011, 21:03

    Interstellar Bill, the love of fantasy over science among the populous is also a deep mystery to me. Why are they enthralled by an adventure were every perceived danger can be averted by the wave of a wand. Perhaps it is because scriptwriters for science fiction seem equally unobliged to live by the rule that escape must be allowed by the laws of physics or their character dies. Another possibility is that audiences tend to hate strict logic and mathematics, and prefer to think solely by analogy.

    In that regard the science fiction film “The Core” is a must see and Hoyle’s novel “The inferno” is a must read. In The Core the scriptwriter is obviously extremely widely read of scientific ideas, but with absolutely no idea how they work! In The Inferno, one of the climaxes of the book, where the novice reveals himself to be an amazingly precocious, has been edited to a footnote in later additions due to the school-level maths involved when he revealed his method. This must have been perceived as an improvement!

  • ljk September 24, 2011, 20:56

    Perhaps everyone involved in the design of a worldship should become familiar with this book:


  • ljk December 19, 2011, 11:41

    Psychology of Space Exploration: Contemporary Research in Historical Perspective (NASA SP-2011-4411) Edited by Douglas Vakoch.

    This new book from the NASA History Series takes a new perspective on the human dimension of spaceflight. Through essays on topics including survival in extreme environments and the multicultural dimensions of exploration, readers will gain an understanding of the psychological challenges that have faced the space program since its earliest days.

    An engaging read for those interested in space, history, and psychology alike, This book is a highly relevant work as we stand poised on the edge of a new era of human spaceflight.

    GPO price hardcover $27.00, GPO price paperback $23.00. Other commercial vendors such as Amazon.com are also expected to sell this book.

    This book is available online for free here:


  • ljk March 5, 2012, 10:46

    Project Enzmann

    by Kelvin F. Long

    Sometime in the 1960s the physicist Robert Duncan Enzmann came up with the idea of using huge spheres of frozen Deuterium, mined from the gas giants, as the main fuel for so called ‘Slow Boats’. These are large vessels but much smaller than conventional world ships.

    Enzmann seems to have imagined these vessels travelling at around 0.09c and taking a crew of 200 to the Alpha Centauri star system in around 60 years. By the time of arrival in the target system, the crew population would have grown to something as large as 2000.

    In the 1970s the space artist David Hardy had painted the Enzmann Starships, although the original picture was lost to history. So in 2011 one of us (Long) commissioned Hardy to repaint the Enzmann and this is shown in the picture below.

    Full article and artwork here:


  • ljk August 29, 2012, 17:11

    “The human heart is as a frail craft on which we wish to reach the stars.”

    – Giotto di Bondone, 1267 – 1337

  • ljk August 31, 2012, 1:47

    How Self-Sustaining Space Habitats Could Save Humanity from Extinction

    George Dvorsky

    This planet can’t protect us forever. Sooner or later, there’ll be a catastrophe that renders this world uninhabitable for humans. And when that day comes, we’ll need to know already how to live in space.

    Yesterday, we explained why we should reboot the Biosphere 2 projects of the 1990s. There are a lot of scientific and technological benefits from learning to create self-sustaining habitats — but the biggest reason is because we need to know how to live in space, before we have noplace else to live.

    There’s little question that this is an important area of inquiry. We clearly want to venture out into space, but if we’re going to do so, we’ll eventually have to lose our dependence on Mother Earth. Colonists won’t always be able to rely on a steady stream of supplies from Earth, which means they’re eventually going to have to figure it on their own.

    Full article here: