World Ships: The Long Journey To The Stars

posted by Kelvin F. Long on August 29, 2011

A World Ship is a very large vehicle many tens of kilometres in length and having a mass of millions of tons, moving at a fraction of a per cent of the speed of light and taking hundreds of years to millennia to complete its journey. It is a self-contained, self-sufficient ship carrying a crew that may number hundreds to thousands and may even contain an ocean, all directed towards an interstellar colonisation strategy.

Artists depiction of Martin/Bond (1984) Worldship Concept.

Progress toward the creation of World Ships relies on much of the same science, engineering and technology as required for interstellar probes. Advances in our understanding of interstellar engineering in general, through projects such as Daedalus, Icarus and others, all feed into the body of knowledge that might support the eventual building of World Ships. Some have questioned why Project Icarus is using mainly fusion-based propulsion, so it’s important to clarify here the purpose of the project. At heart it is a designer capability exercise, which aims to develop the next generation of capable designers who can then do the relevant calculations for a wide suite of problems relating to interstellar research. The design team anticipates that no less than around 80-90% of the thrust generation during the acceleration phase will be via fusion reactions, allowing for 10-20% enhancements from alternative propulsion schemes. So the design team has a watching brief to keep an eye on alternative propulsion systems as well as to learn how to do the engineering and physics calculations. This also extends outside the propulsion area. In fact all elements of spacecraft technology are potentially relevant to Project Icarus, whether small, large, slow, fast or even superluminal. For example, back in 2007 one of us (Long) organized a one-day conference on the ‘warp drive’ at the British Interplanetary Society (BIS) headquarters in London. This was possibly the first ever conference dedicated solely to this concept. This led to several interesting papers, magazine articles and a documentary on interstellar travel. It was at this meeting that Long and the other Project Icarus co-founder Richard Obousy first met each other. Similarly, Pat Galea attended the International Solar Sailing Symposium in New York City in 2010, meeting up with luminaries such as Greg Matloff who is now a consultant to the project. These meetings are important for both Project Icarus, and for interstellar studies in general, as they allow like minded individuals to interact and share ideas. With this in mind, we recently organised a symposium on the World Ship concept in London. The symposium took place on the 17th August 2011, at the BIS headquarters. Just as the warp drive conference was the first of its kind, this may be a first for World Ships. Around 30 people attended the meeting and this included one person who had travelled all the way from Chicago, and another from Toronto, just to attend the meeting. Several other members of the Project Icarus team attended, including Pat Galea (co-chair) and Andreas Hein. Two of the original Project Daedalus Study Group, Alan Bond and Gerry Webb, were also in attendance. Alan Bond had worked on World Ship concepts with Anthony Martin and others in 1984, leading to a famous ‘Red Cover’ version of the Journal of the British Interplanetary Society (JBIS) exploring the history, engineering, finance and sociology relating to World Ships. The purpose of the recent meeting was to review progress in the intervening years, discuss new ideas, and provide for reflection on the classical definition of a World Ship, as provided by Bond and Martin in their 1984 papers. The meeting consisted of several talks (which are listed below and discussed in more detail in a parallel Centauri Dreams article to be posted shortly. The Enzmann Starship: History & Engineering Appraisal, K.F.Long, A.Crowl, R.Obousy Communications Between Worldships, Pat Galea World Ships: The Solar-Photon Sail Option, Greg Matloff World Ships – Architectures & Feasibility Revisited, Andreas Hein Why World Ships?, Gerry Webb A Development Roadmap for the World Ships, Stephen Ashworth On the Financing of World Ships & Other Gigascale Space Projects, Frederik Ceyssens, Maarten Driesen, Kristof Wouters Some important points are worth noting from the symposium discussions. The extensive searching for information on the Enzmann starship by Long, Crowl & Obousy emphasises the importance of aspiring designers to get their concepts down on paper and preferably published in either a peer-reviewed journal or a popular magazine. It is difficult for like-minded physicists and engineers to progress an idea, if the idea itself is not well defined. One of the issues that arose with the Enzmann Starship concept is that members thought the allocated mass available was too small, ranging from 150 tonnes/person at journey start to 15 tonnes/person at journeys end. Galea’s concept for using the Sun’s gravitational focus to communicate with a distance space probe (based on an idea from Claudio Maccone) seemed tantalisingly plausible, although the laser targeting and accuracy requirements, along with the challenging thrust requirements of a relay craft at the focus, make it a difficult system to build in practice. Solar sail concepts for World Ships were presented in a paper by Matloff. The use of solar-photon sails were regarded by some members as having large technical issues, particularly in relation to controlling the continuing oscillations that the sail would experience during the journey. The presentation by Hein laid out a comprehensive way to define the requirements for a World Ship, and to think about the key stepping stones required before such ships could be assembled and launched. The creator of Project Daedalus and one of the authors of the 1984 World Ship papers, Alan Bond, gave Hein’s presentation a big thumbs up. Webb’s very considerable exposition of the link between science fiction ideas, culture, and the construction and launch of a world ship was one of the most entertaining presentations of the day. His presentation led to discussions on the sociology of a world ship, be it democratic or dictatorial in form. Webb envisioned many World Ships being launched to the stars, each containing its own culture (or religion), with the result that only those that possessed the ‘right’ characteristics succeeding; a consequence of Darwinian evolution in action. Ashworth’s very detailed talk on the justifications for world ship construction was one of the highlight lectures of the day. He delivered the lecture in a Presidential address style, demonstrating his excellent skills in articulating his independent thinking. The final talk of the day was given by Ceyssens who argued that we should prepare for World Ship developments today (or other MegaProjects) by building up a seed fund of investments. His specific proposal for his own Millennium Fund Foundation. However, Alan Bond commented with a note of caution that in his opinion it is likely that money, in the way that we understand it, will not be used as a means of controlling resource allocation in the future. All of the presentations were well thought through and provided a variety of insights into an important problem for the future: how to colonise the stars. When studying these huge concepts, one rapidly realises the importance of interstellar (unmanned) precursor missions. These are essential stepping stones to be attained before one could even think about the construction of a World Ship. Concepts like those developed for Project Daedalus and Project Icarus become even more important. We must know a great deal about our destination and the technology to be used before we personally embark on such a trip. Another important requirement is cheap, quick and reusable access to earth orbit for the construction of large vehicles. It is quite clear that conventional launcher technology will not provide for this capability, especially at the expense of around $50,000/kg. The largest mass robotic interplanetary spacecraft put into space to date was the Cassini-Huygens probe at around 2.5 tonnes. If we wanted to put something more massive into orbit perhaps we could use a larger rocket, but there is a practical limit to how big it could be, placing a restriction on the payload mass. So perhaps you could launch two separate rockets, or five or even ten, and then assemble the vehicle in orbit. But how many launches are required before it becomes prohibitively expensive? We need another way. Single Stage to Orbit (SSTO) concepts, such as the Skylon Spaceplane being developed by the UK based Reaction Engines, have the potential to reduce launch costs to as low as $3,000/kg. This is probably the only way that large space based infrastructure capability is going to be built, realistically. The aerospace industry and governments need to realise that if humanity (not just robots) are to have any future in space, then we must be bold and start to invest in this technology now. As Stephen Ashworth argued at the symposium, World Ships will likely be a logical end point to the slow diffusion of our species through the solar system and beyond. World Ships may be many centuries away, but development of routine access to space would be a catalyst to achieving greater things in space, and help us all to direct our energies to more positive ambitions, and realise our purpose in this magnificent cosmos that we inhabit. It’s humbling to think that even if our civilization could manage to launch something as big and ambitious as the Project Daedalus probe, this would be only the starting point for human colonisation of the galaxy. We are a young species and the journey ahead is long, but with optimism, hope and the motivation to keep trying, we will eventually becoming a star-faring civilisation. Some Pictures From The Meeting:  

Kelvin Long Presenting “The Enzmann Starship: History & Engineering Appraisal”


Kelvin Long of Project Icarus (Left) and Alan Bond of Project Daedalus and Now Reaction Engines

Pat Galea Presenting “Communications Between Worldships”


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14 Responses to World Ships: The Long Journey To The Stars

  1. Jasper says:

    Will there be any videos of the talks?

  2. Thanks, Kelvin, for this useful summary of the day.

    Clearly, Skylon or something very like it will be essential to get us off the ground in the first place. But in the context of actually building any kind of interstellar vehicle, most if not all of the mass will not come from Earth at all, so I would suggest that the state of the Earth to space transport system by that time will hardly be relevant. Daedalus sourced most of its mass (propellant) from Jupiter, and the original Bond and Martin article envisaged construction from asteroidal materials. The essential stepping stone here is surely not launching vehicles into orbit as such, but launching infrastructure into orbit which can be used to construct the kind of in-space economy which can build interstellar vehicles. Just as the materials to build the Saturn V were presumably not all imported across the Atlantic from Britain or Europe!

  3. Adam says:

    A related concept would be a “World-Seed” – civilization in embryonic form, able to self-replicate in new environments. The World-Ship is the large end of the scale, but I wonder just how small we could make our technological embryo?

  4. Pingback: Colonizing the Galaxy Using World Ships

  5. kelvin says:

    Hi all, responses to comments thus far.
    Stephen, yes I accept your point that anything an order of magnitude bigger than the ISS will likely need materials resourced from space, off Earth. I meant SSTO as a catalyst to building even bigger things. I don’t accept this is needed for an interstellar mission however, just look at the concepts such as needle probes and the recently proposed microchip probes. Where there is a will?

    Jasper no recording as Pat says, however, look out for a delicious feature article in Spaceflight magazine probably in October or November issue, eye candy and all. Also, the papers will all be submitted to JBIS shortly and this should make for a great issue.

    Adam, world seeds. Yes. I am sure John Hunt has some things to say about that and I would be interested in hearing it.

  6. mike says:

    cyptogon’.com has an informal, unscientific and totally unreliable poll. (sept 16,2011)

    “Within the next 30 years, people will experience video games…
    As memories only, as they share bits of rat meat around a campfire—if they’re lucky (47%, 116 Votes)
    In the mind’s eye, as a result of some implant or electronic link between the brain and a computer (24%, 59 Votes)
    I have no idea (16%, 39 Votes)
    On a screen, but controlling the game via thoughts (this already exists) (9%, 21 Votes)
    On a screen, same as it ever was (4%, 11 Votes)
    Total Voters: 246 ”

    it could be that particular site attracts doomers. the is another such site.

    but.. a certain group of people dont even think there will be video games in 30 years, let alone star ships.

    how can we build star ships with travel times of 100′ s of years while we destroy the earth? i say we dont know squat about ecology. i would imagine “construction” of a star ship would require something more sophisticated than a terrarium.

    it may be possible to send a tin can to the stars but it think it will contain only AI.

    AND…any star ship should have a powerful laser on it. the star ship should send morse code to the earth. when civilization falters people with telescopes can read the message.

    one would need to know what size telescope can see the laser out to what distance. i’m thinking of modest instruments of 75-125mm diameter telescope.

    of course the beam will be pulsed with machine read data, not to mention radio down link. imagine if anyone with a small telescope can actually see the laser signalling morse code.

    the message can transmit how to create a technological society
    to read the machine data encoded in the visual morse code.

    why shouldnt a star ship be a repository of human knowledge?
    sort of an insurance policy on getting data from the mission. this “insurance policy” should be widely publicized with star ship positions archived far and wide. if civilization falters, a beam of light may shorten the dark age.

    one can even sell advertising to be beamed back to earth
    along with PSA’s. it’s a way to get everyone into the mission.

    why, may you ask, am i so pessimistic? maybe because the company i work at just hired someone for ten umerikan dollars an hour. that’s why. if a technological civilization cant provide it’s memebrs with a high standard of living i think it will have trouble launching a star ship, unless the only way to do so is to deny its’ members a living wage. in which case i dont want any part in star ships.

  7. Daniel Alman says:


    “any star ship should have a powerful laser on it. the star ship should send morse code to the earth. when civilization falters people with telescopes can read the message.” – Well lasers are a pretty good ideal on paper but when it comes to focusing such a beam on a target a few light years away, in this case earth, then the problems began to pile up.

    “how can we build star ships with travel times of 100′ s of years while we destroy the earth” – The end goal of such a mission designed by the brilliant icarus, daedalus, etc. teams will be to pave the way off this planet and to the stars. Unfortunately we are long past the point of return in trying to preserve this planet.

    “one can even sell advertising to be beamed back to earth
    along with PSA’s. it’s a way to get everyone into the mission.” I dont think that spectators here on earth will be pretty happy to watch advertisement being beamed back from a spacecraft designed to represent humanity in a near positive fashion. Think of it like having nasa channel flash a KFC commercial every few minutes. Pluss such data for advertisement could take up memory reserved for more important stuff.

  8. Astronist says:

    “if a technological civilization cant provide it’s memebrs with a high standard of living i think it will have trouble launching a star ship”

    Agree completely. Consider how the standard of living has risen over the past 200 years or so since industrialisation took root. Consider how fast it’s rising now, particularly in developing countries like India and China. We absolutely need this trend to continue a long way into the future. That was a point Gerard O’Neill made in regard to building space colonies. Space colonies and starships alike both need and promote greater general prosperity. It’s not either-or, it’s both-and.

    Oxford ,UK

  9. computer says:

    Keep on writing, great job!

  10. Tom Kalbfus says:

    I think worldships will be a means for preserving humanity as it is now. As for AI, they will not need Worldships, they won’t need a life support system, just a computer, memory, and power source for running themselves. I think a human mind can be simulated by a computer, and such simulations will think of themselves as persons.

    The question is what will we do with those flesh and blood humans? I think electronic life forms will threaten to make real humans obsolete, so the question becomes how do we continue to exist after the point of singularity? Worldships offer us a means to seperate ourselves from a post-singularity society if we should so desire, the passengers of such a worldship will of course be self-selecting, though the construction of such worldships could use post-singularity technology and the involvement of AI intellects. I think nanotechnology will play a big role, as we’ll need to harness vast resources in the construction of these Worldships and therefore would need to vastly increase the intelligent workforce in space to do this.

    I have a design for a Worldship I’d like to post somewhere, it is a cross sectional diagram of an inhabited cylinder in space.

    The biggest worldship I can imagine is physically the size of a planet, but not its mass. Imagine a cylinder 20,000 km in diameter, and 20,000 km long with its habitable surface rotating once every 105 minutes to provide 1 Earth gravity equivalent of centrifugal force. While this station is in the Solar System or at its destination, it can use mirrors to reflect sunlight onto its interior, but in flight an artificial illumination source will be used.

    The mirror arrangement uses three mirrors. The cylinder axis is oriented perpendicular to the plane of its orbit around the star, two seperate oval shaped mirrors are placed at a 45 degree angle to incident light rays to the north and south of the open ends of the cylinder, reflecting light into the cylinder, some of that light reflect off a half-parabobic mirror, there are two mirrors inside the cylinder,one to reflect rays coming through the north opening of the cylinder and the other to reflect rays coming through the south opening. The cylinder has an equator which is the midpoint between the ends of the cylinder, this is the equatoral region of the cylinder. The center mirrors rotate a little slower than the habitable interior of the cylinder over a 24 period of time in relation to the inside of the cylinder, as it does so, the sun appears to rise and set inside the cylinder, those regions closer to the ends of the cylinder are cooler and more temperate. 1,000 km high walls at the rims of the cylinder keep in atmosphere, on the insides of the walls are mountain ranges to provide an arctic like climate due to high altitude, the interior of the cylinder contains oceans and continents, total surface area is 2.5 times that of the Earth and a greater percentage of it habitable. As for the support structure, the exterior of the cylinder is not rotating, an interior rotating cylinder is kept separate and supported by magnetic fields as it rotates independently to simulate gravity. The acceleration of the starship itself will be slight, so as not to disturb the environment inside the cylinder. An acceleration of 1 cm per second squared seems about right, no big hurry to get there in a ship as big as this, so long as you have sufficient fuel to provide both for propulsion and artificial illumination when not orbiting a star.

  11. Roger Hitching says:

    Your article looked long and boring, if you want to attract more people think of them not the people who are on board already but those you want on board. Put in a few paragraphs then some pictures think of yourself as writing for a tabloid not 1980 Times paper. Widen your audience do not become a few people talking talking to a few people.

  12. Flor says:

    If one of those world ships was built in earth orbit it would create millions of jobs on earth and its inhabitants would industrialize the entire solar system .If the EU agreed to increase its population and put everybody to work it would solve many of the present problems.

  13. 30 may 2014 earth
    re:Icarus worldship
    hmmm well a good concept, a lot of variables though but carry on david
    ps”are you living for love?” B. K. Hughes 1948-1998 USA

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