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Starflight: A Multi-Generational Perspective

“While other nations try to reach the moon, we are trying to reach the village,” said Julius Nyerere, who after serving as Tanzania’s first president retired to the village of his childhood. Mae Jemison likes to use this quote to introduce what she sees as a major theme of the 100 Year Starship project, which is that as we look for the extraordinary, we have the opportunity to impact things today. The connection between future and present is pivotal because spinoffs happen, and so does philosophy. Space is another platform from which to see ourselves.

It’s estimated that 500 million people watched Neil Armstrong step out onto the moon, the largest television audience for a live broadcast to that time. That impacts education and the making of careers as the surge in technicians and researchers in the Apollo era translates to role models for children and goals for the culture at large. In her opening address to the 100 Year Starship Symposium in Houston, Jemison said that the project’s goal is not to create a specific technology but to encourage a framework of ideas from which spinoffs occur:

“Radical leaps go beyond our personal experience, and farther than our eyes can see. Our goal is to foster radical leaps in technology that can only happen as the result of tackling a very difficult problem. We are not focused on launching an interstellar mission ourselves. We are focused on nurturing the environment for people to think about how it can be done one day, in the belief that by pursuing the extraordinary, we also create a better world today.”

expo-inspire

Image: Outreach at the 100 Year Starship Symposium. A shot of activity at the event called Expo Inspire, billed as an all-day learning experience with focus on space and science.

Jemison had just returned from the Jet Propulsion Laboratory, as had Claudio Maccone and Les Johnson, where a specific technology was beginning to come into focus. Centauri Dreams readers will know of my interest in the Innovative Interstellar Explorer mission concept developed by Ralph McNutt and his team at Johns Hopkins University’s Applied Physics Laboratory. McNutt was at the JPL meetings as well, where the topic was an interstellar precursor mission much in the same mode, a trip to 200 AU and beyond.

Once New Horizons reaches Pluto/Charon next summer, we will have no instrumented encounters in the outer Solar System unless a suitable flyby object in the Kuiper Belt can be identified. A probe to 200 AU and beyond, specifically designed as an interstellar precursor, would be the successor not just to New Horizons but to the Voyagers, whose journeys have fired the imagination of more than one generation. At our present state of readiness, even 200 AU is an extreme hurdle that demands innovation in propulsion and instrumentation.

In a way, this is a descendant of the TAU mission of the 1980s. TAU stood for Thousand Astronomical Units, a mission concept that grew out of a 1976 conference called ‘Missions Beyond the Solar System’ that was held at JPL. It’s quite a target: 1000 AU is 25 times the distance between the Sun and Pluto. In 1984, Lew Allen, then director of JPL, asked Aden and Marjorie Meinel to put together a team to figure out how to make the mission happen. The resulting study called for a small nuclear reactor-driven ion drive using xenon, with the goal of reaching 100 kilometers per second after ten years of sustained thrust. The 1000 AU target would be roughly 50 years away, with a launch thought to be possible by 2010.

tau3

Image: One configuration of the TAU mission. Note the Pluto orbiter to be dropped off along the way. Interesting to speculate on the power requirements for that particular add-on.

The TAU mission never flew, like many design concepts that nonetheless contribute to the evolving framework of ideas that move the subject forward. We’ll keep a close eye on the latest JPL study. Meanwhile, the work on getting places faster continues to churn up new ideas elsewhere. At a session in the Propulsion & Energy track in Houston, David Chesney (Florida Institute of Technology) explored what he calls a Magnetic Reconnection Rocket, one that trades off things we observe in the Solar System. The solar wind blows particles out from the Sun into the heliosphere, at speeds between 400 and 800 kilometers per second. Coronal mass ejections can drive matter outwards at up to 3000 kilometers per second.

Are there possibilities here? The phenomenon of magnetic reconnection happens in plasmas, converting magnetic energy into kinetic and thermal energy and driving particle acceleration. Loop structures emerge in the solar atmosphere as a result of the phenomenon as field lines connect and disconnect with each other, releasing vast amounts of energy and further heating the plasma. What Chesney hopes to do is to reproduce this effect to produce reconnection in a much smaller area, offering higher thrust than conventional ion thrusters and, as Chesney describes it, taking ion propulsion to orders of magnitude higher efficiency.

magreconnect

Image: David Chesney explains the Magnetic Reconnection Rocket.

We’re out on the cutting edge here, dealing with a phenomenon that is not well understood. In fact, NASA has a mission called Magnetospheric Multiscale that is being developed at GSFC that involves not one but four spacecraft that will launch on a single rocket and fly in formation to study how magnetic reconnection changes the magnetic environment near the Earth, in the process sending fast moving particles into space with intense bursts of energy. Chesney believes the FIT work could lead to ion engines with higher efficiency and scalability.

We develop the things we need by studying the parameters of the problem to be solved, and when we make the problem truly difficult — the very definition of a starship — we open up a wave of speculation, theory and experiment. Interstellar missions in a rational timeframe (I define this as one century or less to another star) have no solution we can engineer today, which is why we keep all the lines of study open and stay alert for the outlier that may surprise everyone. Out of this new technologies emerge, with effects on society and culture we have yet to imagine. Push the process and you eventually get hardware. Keep pushing.

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Comments on this entry are closed.

  • Andrew LePage September 24, 2014, 13:02

    The ion propulsion system proposed for TAU was a bit before its time considering that the first space-based ion propulsion test took place only 50 years ago and the first regular use of the technology in spacecraft only started in the last couple of decades. Hopefully with the success of the Dawn mission to Vesta and (fingers crossed!) Ceres, this technology will be deemed mature enough to attempt TAU-like missions into deep space.

    http://www.drewexmachina.com/2014/07/20/50-years-ago-today-the-first-ion-engine-test-in-space/

  • Geoffrey Hillend September 24, 2014, 18:15

    Someone finally mentioned VASIMR. Horay! VASIMR is a plasma propulsion rocket even before we’ve completed the first fusion reactor. It needs a nuclear reactor to get the highest specific impulse and with that might it be the fastest thing we have available today?

  • Mike Jude September 24, 2014, 21:15

    How to say this gently…I think Mae Jemison is misguided. The fundamental question is not how we can drag the entire human race up by its bootstraps in order to go to another star. Imagine if Columbus had been constrained by the notion that first the entire European, or even just the Spanish, population had to be convinced that the world was round before he could set out to prove it. Would he have ever gone? Doubtful.

    I think that the answer here is pretty simple….just go! What kind of technology do we have to get to another star? Not 100 years from now…right now. Comparatively primitive, right? OK, well do it anyway. Launch a second generation ion drive probe straight at Alpha Centauri. Justify it on the basis of exploring the heliopause in more detail or something, but ensure that the trajectory is towards the nearest star. Would it actually get there? maybe not, but people would understand that we had made the effort. Several years later, when the technology improves, launch another one. Instead of 100 years to doing anything and then only after solving world hunger and every other horrible you can think of, we would actually be building and launching hardware. You don’t learn about interstellar space by speculation, you learn about it by going there…..frequently.

    This is why the 100YSS is ultimately doomed, in my opinion. It doesn’t actually do anything….it simply talks and makes politically correct pronouncements designed to give the impression that something is happening.

    One of these days someone will head off to the stars, probably for the most mundane and politically incorrect reasons and people will forget that there ever was a 100YSS project at all. IMHO :-)

  • Charley September 24, 2014, 21:31

    I wish to provide a moment of reflection here. I’d like to gently admonish Mr. Gilster for his failure to give us a ‘heads up’ that this symposium was scheduled and that we should hear about it only at the last minute. There seems to have been no advanced announcement that this would be held.

    Additionally, I’ve seen no links to the symposium that showed it was available to be viewed live on the Internet for those who were interested in tuning in. Do such links exist for the recorded sessions that were held ? Was there any further discussion on the concept of warp drive by Miles Davis or will he be making himself available online later on in the days ahead ? Some questions could be addressed to individuals who spoke at the symposium. If they were to give their inputs to Centauri Dreams.

  • Antonio September 25, 2014, 5:57

    @Geoffrey: VASIMR doesn’t have the highest specific impulse. Most ion thrusters in use today have Isp higher than VASIMR. The difference is in thrust, not Isp. VASIMR has a thrust intermediate between ion rockets and chemical rockets. VASIMR is not useful for missions beyond Saturn-Uranus because it has a low Isp.

  • Paul Gilster September 25, 2014, 8:03

    Charley writes:

    I wish to provide a moment of reflection here. I’d like to gently admonish Mr. Gilster for his failure to give us a ‘heads up’ that this symposium was scheduled and that we should hear about it only at the last minute. There seems to have been no advanced announcement that this would be held.

    Charley, I wrote up the 2014 schedule in “Interstellar Conferences for 2014”:

    https://www.centauri-dreams.org/?p=30536

    but I do regret not updating it later in the summer as a reminder.

    On the other point:

    Additionally, I’ve seen no links to the symposium that showed it was available to be viewed live on the Internet for those who were interested in tuning in. Do such links exist for the recorded sessions that were held ? Was there any further discussion on the concept of warp drive by Miles Davis or will he be making himself available online later on in the days ahead? Some questions could be addressed to individuals who spoke at the symposium. If they were to give their inputs to Centauri Dreams.

    I have no information about video, but will pass it along as soon as I hear anything. On warp drive, I assume you mean Eric Davis, although Miles Davis is one of my favorite musicians ;-) In fact, my son is named Miles, which probably brought the name to mind. And no, Eric didn’t discuss warp drive issues at the Symposium. He does tell me that he’s working on a piece for Centauri Dreams discussing these matters.

  • Michael Spencer September 25, 2014, 8:56

    Mr. Jude: Point taken, but do keep in mind that Columbus had to convince the folks WITH money that they would make MORE money by finding a shorter way to the Indies. They just happened to fins a New World along the way.

    Until we find a way to make space pay- natural resources processed in situ or brought to earth, for example- nothing substantial is going to happen.

    I’m reminded of NASA’s crazy notion for Mars exploration, a notion that presumes Earth would finance a colony. It’s laughable. Just ask the Moonies up there in Armstrong Station. They will tell you that they had to smelt aluminum themselves and they had to bring water from the ‘belt.

    Our tech is so stunningly primitive that we can’t even jockey a satellite on orbit- we discard multi-million dollar birds for want of fuel in the same way that we discard multi-million dollar vehicles getting to orbit. Our tech is more primitive than the Santa Maria, comparatively.

    So, to the dreamers like myself who yearn for lives a millennium from now, when Earth has developed a true system-wide infrastructure, let us dream on. Meanwhile, start building that economic base that will take us to the stars. An earth-based economy will never afford it or sustain it.

    Oh. And yea. I will be at the next symposium, dreaming and yearning with Paul and the other denizens of the sometime-future.With smiles and a longing heart born, alas, in the wrong millennium.

  • ljk September 25, 2014, 8:59

    Mike Jude said on September 24, 2014 at 21:15:

    “How to say this gently…I think Mae Jemison is misguided. The fundamental question is not how we can drag the entire human race up by its bootstraps in order to go to another star. Imagine if Columbus had been constrained by the notion that first the entire European, or even just the Spanish, population had to be convinced that the world was round before he could set out to prove it. Would he have ever gone? Doubtful.”

    Mike Jude, you are a breath of fresh air! You have brought up one of my biggest pet peeves, where a member of the unwashed says “Why are we spending so much money on space when there are so many problems to solve right here on Earth?!” That kind of ignorance deserves to be lambasted and put down and anyone who does not understand why does not have all the facts. This is one big reason why we don’t have a manned base on Mars or a probe heading of to Alpha Centauri – and the various space agencies and advocates are not doing enough to counter this tide of ignorance.

    Then Mike Jude said:

    “I think that the answer here is pretty simple….just go! What kind of technology do we have to get to another star? Not 100 years from now…right now. Comparatively primitive, right? OK, well do it anyway. Launch a second generation ion drive probe straight at Alpha Centauri. Justify it on the basis of exploring the heliopause in more detail or something, but ensure that the trajectory is towards the nearest star.”

    Again, amen brother! Way too much time and energy is focused on warp drives when we should be focusing on the technologies and physics that actually exist. Yes it may not get us to Alpha Centauri in 10 minutes but this is reality, not some TV series. We either play by the rules of the Universe or we wait for a real starship forever.

    And I am tired of those who just assume some magical genius in the future is going to solve all these problems. No, friends, it is called doing real research and work, just like the rocket scientists and engineers of old did to start the Space Age: They didn’t wait around for some guy decades down the road to get us into space and to the Moon, they got together and built the actual rockets and spaceships required for the job. And oh yes, there were problems and accidents and delays and even fatalities, but that is what happens when you actually work on something big and complex to make it a reality.

    Then Mike Jude said:

    “This is why the 100YSS is ultimately doomed, in my opinion. It doesn’t actually do anything….it simply talks and makes politically correct pronouncements designed to give the impression that something is happening.”

    I am so glad someone actually said the Emperor has no clothes. DARPA just wanted to get free info and tech from the eager young space nerds who were so excited that someone actually seemed to pay attention to them and their ideas about space travel. The military couldn’t care less about going to Alpha Centauri and they are only in space to use it as the ultimate high ground. 100YS is a dog and pony show with an underlying motive that has nothing to do with interstellar travel.

    And a final word from Mike Jude:

    “One of these days someone will head off to the stars, probably for the most mundane and politically incorrect reasons and people will forget that there ever was a 100YSS project at all. IMHO :-)”

    Humanity’s first interstellar travelers – the ones who will go to the stars in person, not just our machines – will not be the astronauts and cosmonauts we have seen for the last half century. They will be entrepreneurs, cultists, criminals, and the politically oppressed, the latter group coming from all the other groups I just mentioned. Who were the first people from Europe to reach the Americas? Not altruistic scientists, that is for darn sure. They came for material wealth first and foremost. Anything else was a bonus – unless you happened to be on the receiving end of their business plans.

    NASA and DARPA will not give us the galaxy. A bunch of rich guys who want to literally carve out a planetoid and put themselves and all their acolytes aboard and sail off into the sunsets just might, though.

  • Alex Tolley September 25, 2014, 12:14

    The 100yss website indicates that there was no live streaming. The plenary sessions were recorded and will be put online starting end of October.

    I look forward to watching some of them.

  • Alex Tolley September 25, 2014, 12:49

    @Mike Jude.

    I think Mae Jemison is misguided. The fundamental question is not how we can drag the entire human race up by its bootstraps in order to go to another star. Imagine if Columbus had been constrained by the notion that first the entire European, or even just the Spanish, population had to be convinced that the world was round before he could set out to prove it.

    I wasn’t there, so I cannot comment on this. If the idea is that we could use the spinoffs to help Earth society, then I do not see why this would be a bad thing.

    The problem with the Columbus analogy is that Columbus was financed by Queen Ferdinand. Her subjects didn’t get any input on whether this was a good use of the funds for Spain. This is not going to happen in a modern democracy where we can make a fuss about misdirected spending priorities (even if i has little impact). Whatever the outcome of Columbus’ commercial idea (a better route to the Indies), it would have been known within a few years. A stellar probe using contemporary technology won’t get very far even in a generation. If it sucks up significant resources, arguably they may be largely wasted.

    While impatient, I think there is certainly some value in waiting until better technologies emerge. We’ve talked about miniaturized craft, perhaps flying in swarms as a possible low cost probe. We’ve talked about use of beamed sails to avoid the issues of the rocket equation. These technologies are certainly not mature enough today, but in 25+ years? I also think it is going to be easier to build space based solar power and laser asteroid deflectors first, which benefit humanity, then use those technologies to launch probes. This is rather like the retirement of those 2 spy sats for use by Nasa.

    Using the Columbus analogy, it would be if Spain decided to build more seaworthy ships in order to allow ships to reach their destinations without hugging the coast to cut the corners of the trips so that trade goods to get to Spain faster/cheaper. Then Columbus using one of those ships to test how far he could go west, perhaps to test if the sea route west was shorter than the sea route around the coasts or across land.

    Star ship building is so incredible expensive that it will need centuries of economic growth (assuming we can do this) before we can build those behemoths of the imagination. We can reduce this requirement by making small devices that cost a fraction of the large rockets and by using “dual use” technologies whose still enormous cost can be justified as beneficial for the Earth – asteroid defense and 24/7 clean power. Then instead of trying to find a way to fund a star ship/probe a century or more from now, almost all of the building blocks will be in place to be used.

    In 100 years, I would bet that brain simulation would allow a human mind to be carried to the stars, experience the destination embodied in a printed humaniform shell, and perhaps return the same way too tell Earth “I have seen things you people wouldn’t believe….”

  • Geoffrey Hillend September 25, 2014, 15:47

    @Antonio I already know that VASIMR does not have the highest specific impulse and ion thrusters have higher specific impulse. I guess I was thinking more down the lines of Mike Jude: just build something now and send it out there. VASIMR still is the fastest thing that can carry astronauts through the solar system that AD ASTRA has proposed, so I was toying with the idea someone can go along on the trip as has David Chesney but I guess we will have to wait until fusion rockets become available or something better? I read somewhere in a magazine in 2008 that a rocket with nuclear fusion propulsiont has the potential for a specific impulse of one million!!!

    It is painfully obvious when money is involved a great deal of planing is going to come first. I’m just as impatient as the next person. We always have to have forums, seminar and symposiums etc so new ideas can be generated.

    I think I and many others who could not be free to go to it have found the 2013 100 years starship symposium video posted online on youtube very inspiring especially when it comes to visionary technology like space warps, warp drive etc which is what I have a intense interest, and also I am thankful for it since we can keep up to date with what are the latest development in these and other ideas etc. so I hope they continue to have them every year.

  • Alex Tolley September 25, 2014, 17:51

    Not only should we not assume magical technology from a “genius”, but also magical economic growth, both on Earth and in space. New technology is not determinable in advance. Economic growth can be planned to some extent, but if we need a solar system sized economy, then there must be a viable path with key technologies to economics to support this.

    However, we should also understand that the “just do it, now, now, now” also makes no sense if the technology is inadequate. We are like C17th europeans discussing building a global airline transportation system with ballons and human power. With lightweight steam engines, dirigibles could have been imagined, but not airplane (perhaps ornithopters could have been imagined, even though they are not practical). Since we can see miniaturization and beamed sails, why not wait until these technologies are ready before sending out probes? As for humans in large ships, even worldships, they are so far away that the best we can do is develop systems, like closed loop recycling which would be useful for Earth cities and manned solar system missions. We should also be aware that sending human meat puppets in worldships may never make any sense or ever be affordable by even the wealthiest economy or solar system oligarch. Designing such ships may be exercises in futility, and will certainly be if “magic” technology does appear.

    If we want to know what is out there, then telescope development is the way to go, both cis-lunar and at the solar gravitational focus.Semding a probe to alpha-centauri without even knowing if teh system has any planets (even gas giants) makes little sense except as a long term stunt. Better to choose a more interesting target, preferably one wit a life bearing world.Not only should we not assume magical technology from a “genius”, but also magical economic growth, both on Earth and in space.

  • Antonio September 26, 2014, 5:07

    Geoffrey Hillend said:

    “I already know that VASIMR does not have the highest specific impulse and ion thrusters have higher specific impulse. I guess I was thinking more down the lines of Mike Jude: just build something now and send it out there.”

    Then there is no reason to use VASIMR. We used already ion propulsion in many spacecraft (most telecom satellites today use ion propulsion). VASIMR has never been used in space.

    He also said:

    “VASIMR still is the fastest thing that can carry astronauts through the solar system that AD ASTRA has proposed, so I was toying with the idea someone can go along on the trip as has David Chesney but I guess we will have to wait until fusion rockets become available or something better?”

    VASIMR can’t carry astronauts to any interesting place in the Solar System, not least interestellar space. If you want to send a probe to 200 AU now, the only option is ion propulsion. If you want to send astronauts to the Moon or Mars, the only option is chemical propulsion.

    http://www.youtube.com/watch?v=myYs4DCCZts

  • Matt September 26, 2014, 15:34

    @Mike Jude

    I have been following the 100YSS from the beginning; I am pretty sure they will not wait till all problems are solved on earth before building a star ship. You objection is mostly a straw man argument. 100YSS is just saying we should share and cooperate, I don’t think that needs to be controversial.

    I do share your impatience, I would like us to start launching missions now. Actual missions to other starts are not currently practical, but various kinds of precursor missions are.

  • Geoffrey Hillend September 26, 2014, 15:51

    Worldships may also become obsolete if we get better technology like anti-matter drives or warp drives. It makes sense to have a target first such as an Earthlike planet and spending money on better space telescopes with interferometers for exoplanet spectroscopy, but we can still plan and design interstellar spacecraft in the meantime.

    VASIMR does need megawatts of power to function at full specific impulse but even at its present 200 kw power, it has a much higher trust than ion propulsion. Ion power also has electrode erosion on the grids unless it is a hall thruster. I still see VASIMR playing a major role in the future of manned exploration of our solar system. It’s who has the working technology first that will get the bid.

    What about a rocket which is a large battery or contains many rechargeable batteries with solar power. It could be docked in space with a VASIMR spacecraft to give it more power instead of a nuclear reactor which is harder to make small enough to be sent into space.

  • Antonio September 26, 2014, 19:15

    No matter how many times you say it, VASIMR has NOT enough thrust/mass ratio for manned missions. It will be simply too slow. And batteries have very poor energy density. Nuclear reactors are way better, but still not enough for VASIMR to be used in manned missions. Simply do the math.

  • Alex Tolley September 27, 2014, 11:55

    @Antonio – VASIMR and ion thrusters have about the same Isp at low thrust. The whole point of VASIMR is to provide variable thrust for different phases of a mission. The criticisms are more about practicality, e.g. the size of the reactor to power it in high thrust mode, especially for a large ship Obviously we cannot use the technology today for a manned mission, similarly with NTRs, but I don’t see your argument that it has no role for manned missions in the solar system and only chemical rockets will get you to Mars. This may be true if you want to go very soon, but not if you can wait for technology development.

  • Mark Zambelli October 1, 2014, 14:16

    @Paul Gilster

    “Eric didn’t discuss warp drive issues at the Symposium. He does tell me that he’s working on a piece for Centauri Dreams discussing these matters.”

    I for one am very much looking forward to that if he can.

    Now as for sending out interstellar missions early, I don’t really want to be the one to say it, but the main reason for doing this now would be purely for the inpirational value of such a venture (and I certainly don’t think this is a bad idea at all). The reason why I’m caught-in-the-headlights (or fusion exhaust plume) and can’t decide what to do for the best is the following… how long would it take to crawl to Alpha Centauri if we sent out our first probe tomorrow? Now wait 50 years and send out the next with its better tech… flighttimes reduced, yay, but still in the order of centuries(?). Another few decades wait and out goes our next probe… each one faster than the last, and so on.

    I can foresee each subsequent attempt overtaking the previous probe so the one that arrives first may well be the one sent last. If we’re talking generational ships then what kind of mindset would be needed for those early crews knowing that they will be overtaken by their descendants who stayed home waiting for better tech/advances? (Now for a display of imperfect-recall… I think that Asimov (?) wrote a short story along those lines (spoiler alert) when he described a generational ship arriving at their destination only to be greeted by the society that had sprung up in the meantime from faster, later ships).

    That being said, I’m all for sending out probes as soon as we get the right technology as the alternative is to keeping holding-off but then centuries would pass and we wouldn’t learn from our successes/failures. I’d love to hear more from anyone who has opinions on this.

    ljk made a great deal of sense when saying…

    “Humanity’s first interstellar travelers – the ones who will go to the stars in person, not just our machines – will not be the astronauts and cosmonauts we have seen for the last half century. They will be entrepreneurs, cultists, criminals, and the politically oppressed, the latter group coming from all the other groups I just mentioned.”

    Another group may be ‘adventurers’ with the subsets of ‘thrill-seekers’ and ‘explorers’ with motives of fame and discovery respectively.

  • Mark Zambelli October 1, 2014, 14:36

    In my first paragraph above I have made a distinction between 1) the IIE and TAU type missions that are driven by their near-term science goals and that happen to be aimed at stellar systems for far-future encounters and 2) true near-term (100yr) interstellar missions that will glean data from 250-1000 AU only as a matter-of-course as they ‘quickly’ pass through the region under constant acceleration.

    I think the former would precede the latter for two reasons, namely the ISM would need characterising prior to a longer, perhaps relativistic, journey, and that the technology would seem to be nearer for the IEE type missions.

  • ljk December 17, 2014, 15:08

    December 11, 2014

    Interstellar Generation Ship Challenges

    The TV show Ascension has a plot that a Project Orion style interstellar generation ship was launched in 1963.

    Ignoring the challenge of needing many times the number of nuclear bombs that were ever made for an Interstellar project Orion there are other issues.

    We have not solved a space portable sustainable artificial ecosystem. Icarus Interstellar has Project Persephone now. It is the research is looking at how a long-duration manned mission out of the solar system could feasibly survive. Any future ‘generation ship’ we build will need to be entirely self-sustainable in terms of not only food and water, but cultural advances as well. In essence, any manned vehicle we one day send into interstellar space will need a ‘flourishing ecosystem’.

    Project Persephone aims to develop a design approach for a worldship to underpin truly ecological architectural practices, in which matter can be attributed with agency. This requires us to think much more broadly about the performance and innate creativity of the materials we use.

    http://nextbigfuture.com/2014/12/interstellar-generation-ship-challenges.html?m=1