I grew up on generation ship stories. I’m thinking of tales like Heinlein’s Orphans of the Sky, Aldiss’ Non-Stop, and (from my collection of old science fiction magazines) Don Wilcox’s “The Voyage that Lasted 600 Years.” The latter, from 1940, may have been the first generation ship story ever written. The idea grows out of the realization that travel to the stars may take centuries, even millennia, and that one way to envision it is to take large crews who live out their lives on the journey, their descendants becoming the ones who will walk on a new world. The problems are immense, and as Alex Tolley reminds us in today’s essay, we may not be fully considering some of the most obvious issues, especially closed life support systems. Project Hyperion is a game attempt to design a generation ship, zestfully tangling with the issues involved. The Initiative for Interstellar Studies is pushing the limits with this one. Read on.
by Alex Tolley
“Space,” it says, “is big. Really big. You just won’t believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just peanuts to space..” The Hitchhikers Guide to the Galaxy – Douglas Adams.
Detail of book cover of Tau Zero. Artist: Manchu.
Introduction
Science fiction stories, and most notably TV and movies, avoid the fact of the physical universe being so vast by various methods to reduce travel time. Hyperspace (e.g. Asimov’s galaxy novels), warp speed (Star Trek), and wormholes compress travel time to be like that on a planet in the modern era. Relativity will compress time for people at the cost of external time (e.g. Poul Anderson’s Tau Zero). But the energy cost of high-speed travel has a preferred slow-speed method – the space ark. Giancarlo Genta classifies this method of human crewed travel: H1 [1]. a space-ark type, where travel to the stars will take centuries. Either the crew will be preserved with cryosleep on the journey (e.g. Star Trek TOS S01E22, “Space Seed”) or generations will live and die in their ship (e.g. Aldiss Non-Stop) [2].
This last is now the focus of the Project Hyperion competition by the Initiative for Interstellar Studies (i4is) where teams are invited to design a generation ship within various constraints. This is similar to the Mars Society’s Design a City State competition for a self-supporting Mars city for 1 million people, with prizes awarded to the winners at the society’s conference.
Prior design work for an interstellar ship was carried out between 1973 and 1978, by the British Interplanetary Society (BIS). It was for an uncrewed probe to fly by Barnard’s star 5.9 lightyears distant within 50 years – their Project Daedalus.[3] Their more recent attempt at a redesign, the ironically named Project Icarus, failed to achieve a complete design, although there was progress on some technologies [4] Project Hyperion is far more ambitious based on the project constraints including human crews and a greater flight duration .[5].
So what are the constraints or boundary conditions for the competition design? Seven are given:
1. The mission duration is 250 years. In a generation ship that means about 10 generations. [Modern people can barely understand what it was like to live a quarter of a millennium ago, yet the ship must maintain an educated crew that will maintain the ship in working order over that time – AT].
2. The destination is a rocky planet that will have been prepared for colonization by an earlier [robotic? – AT] ship or directed panspermia. Conditions will not require any biological modifications of the crew.
3. The habitat section will provide 1g by rotation.
4. The atmosphere must be similar to Earth’s. [Presumably, gas ratios and partial pressures must be similar too. There does not appear to be any restriction on altitude, so presumably, the atmospheric pressure on the Tibetan plateau is acceptable. – AT]
5. The ship must provide radiation protection from galactic cosmic rays (GCR).
6. The ship must provide protection from impacts.
7. The crew or passengers will number 1000 +/- 500.
The entering team must have at least:
- One architectural designer
- One engineer
- One social scientist (sociologist, anthropologist, etc.)
Designing such a ship is not trivial, especially as unlike a Lunar or Martian city, there is no rescue possible for a lone interstellar vehicle traveling for a quarter of a millennium at a speed of at least 1.5% of lightspeed to Proxima, faster for more distant stars. If the internal life support system fails and cannot be repaired, it is curtains for the crew. As the requirements are that at least 500 people arrive to live on the destination planet, any fewer survivors, perhaps indulging in cannibalism (c.f. Neal Stephenson’s Seveneves), means this design would be a failure.
Figure 1. Technology Readiness Levels. Source NASA.
The design competition constraints allow for technologies at the technology readiness level of 2 (TRL 2) which is in the early R&D stage. In other words, the technologies are unproven and may not prove workable. Therefore the designers can flex their imaginations somewhat, from propulsion (onboard or external) to shielding (mass and/or magnetic), to the all-important life support system.
Obviously, the life support system is critical. After Gerry O’Neil designed his space colonies with interiors that looked rather like semi-rural places on Earth, it was apparent to some that if these environments were stable, like managed, miniature biospheres, then they could become generation ships with added propulsion. [6]. The Hyperion project’s 500-1500 people constraint is a scaled-down version of such a ship. But given that life support is so critical, why are the teams not required to have members with biological expertise in the design? Moreover, the design evaluators also have no such member. Why would that be?
Firstly, perhaps such an Environmental Control and. Life Support System (ECLSS) is not anticipated to be a biosphere:
The requirements matrix states:
ECLSS: The habitat shall provide environmental control and life support: How are essential physical needs of the population provided? Food, water, air, waste recycling. How far is closure ensured?
Ecosystem: The ecosystem in which humans are living shall be defined at different levels: animals, plants, microbiomes.
This implies that there is no requirement for a fully natural, self-regulating, stable, biosphere, but rather an engineered solution that mixes technology with biology. The image gallery on the Hyperion website [5] seems to suggest that the ECLSS will be more technological in nature, with plants as decorative elements like that of a business lobby or shopping mall, providing the anticipated need for reminders of Earth and possibly an agricultural facility.
Another possibility is that prior work is now considered sufficient to allow it to be grafted into the design. It seems the the problem of ECLSS for interstellar worldships is almost taken for granted despite the very great number of unsolved problems.
As Soilleux [7] states
“To date, most of the thinking about interstellar worldships has focused, not unreasonably, on the still unsolved problems of developing suitably large and powerful propulsion systems. In contrast, far less effort has been given to the equally essential life support systems which are often assumed to be relatively straightforward to construct. In reality, the seductive assumption that it is possible to build an artificial ecosystem capable of sustaining a significant population for generations is beset with formidable obstacles.”
It should be noted that no actual ECLSS has proven to work for any length of time even for interplanetary flight, let alone centuries for interstellar flight. Gerry O’Neill did not make much effort beyond handwaving for the stability of the more biospheric ECLSS of his 1970s-era space colony. Prior work from Bios 3, Biosphere II, MeLISSA, and other experiments, has demonstrated very short-term recycling and sustainability, geared more towards longer duration interplanetary spaceflight and bases. Multi-year biospheres inevitably lose material due to imperfect recycling and life support imbalances that must be corrected via venting. The well-known Biosphere II project couldn’t maintain a stable biosphere to support an 8-person crew for 2 years, accompanied by a 10% per year atmosphere loss.
On a paper design basis, the British Interplanetary Society (BIS) recently worked on a more detailed design for a post-O’Neill space colony called Avalon. It supported a living interior for 10,000 people, the same as the O’Neill Island One design, providing a 1g level and separate food growing, carbon fixing, and oxygen (O2) generating areas. However, the authors did not suggest it would be suitable for interstellar flight as it did require some inputs and technological support from Earth. Therefore it remains an idea, and as with the hardware experiments to date, such ECLSSs remain at low TRL values. While the BIS articles are behind paywalls, there is a very nice review of the project in the i4is Principium magazine [7].
Table 1. Inputs to support a person in Space. Source: Second International Workshop on Closed Ecological Systems, Krasnoyarsk, Siberia, 1989 [8]
Baseline data indicates that a person requires 2 metric tonnes [MT] of consumables per year, of which food comprises 0.2 MT and oxygen (O2) 0.3 MT. For 1000 people over 250 years that is 500,000 MT. To put this mass in context, it is about the greatest mass of cargo that can be carried by ships today. Hence recycling to both save mass and to manage potentially unlimited time periods makes sense. Only very short-duration trips away from Earth allow for the consumables to be brought along and discarded after use, like the Apollo missions to the Moon. Orbiting space stations are regularly resupplied with consumables, although the ISS is using water recycling to save on the resupply of these consumables for drinking, washing, and bathing.
If an ECLSS could manage 100% recycling, then if the annual amount is the buffer to allow for annual crop growth, the ship could support the crew over the time period with just over 2000 MT, but of course with the added requirement for power and infrastructure and replacement parts to maintain the ECLSS.
Figure 2. Conceptual ECLSS process flow diagram for the BIS Avalon project.
A review of the Avalon project’s ECLSS [7] stated:
“A fully closed ECLSS is probably impossible. At a minimum, hydrogen, oxygen, nitrogen, and carbon lost from airlocks must be replaced as well as any nutrients lost to the ecosystem as products (eg soil, wood, fibres, chemicals). This presents a resource-management challenge for any fully autonomous spacecraft and an economic challenge even if only partially autonomous…Recycling does not provide a primary source of fixed nitrogen for new plant growth and significant quantities are lost to the air as N2 because of uncontrollable denitrification processes. The total loss per day for Avalon has been estimated at 43 kg to be replaced from the atmosphere.”
[That last loss figure would translate to 390 MT for the 1/10 scaled crewed Hyperion starship over 250 years.]
Hempsell evaluated the ECLSS technologies for star flight based on the Avalon project and found them unsuited to a long-duration voyage [9]. It was noted that the Avalon design still required inputs from Earth to be maintained as it was not fully recycled:
“So effective is this transport link that it is unlikely Earth orbiting colonies will have any need for the self-sufficiency assumed by the original thinking by O’Neill. It is argued that a colony’s ability to operate without support is likely to be comparable to the transport infrastructure’s journey times, which is three to four months. This is three orders of magnitude less than the requirements for a world ship. It is therefore concluded that in many critical respects the gap between colonies and world ships is much larger than previous work assumed.”
We can argue whether this will be solved eventually, but clearly, any failure is lethal for the crew.
One issue is not mentioned, despite the journey duration. Over the quarter millennium voyage, there will be evolution as the organisms adapt to the ship’s environment. Data from the ISS has shown that bacteria may mutate into more virulent pathogens. A population living in close quarters will encourage pandemics. Ionizing radiation from the sun and secondaries from the hull of a structure damages cells including their DNA. 250 years of exposure to residual GCR and secondaries will damage DNA of all life on the starship.
However, even without this direct effect on DNA, the conditions will result in organisms evolving as they adapt to the conditions on the starship, especially the small populations, increasing genetic drift. This evolution, even of complex life, can be quite fast, as the continuing monitoring of the Galápagos island finches observed by Darwin attests. Of particular concern is the creation of pathogens that will impact both humans and the food supply.
In the 1970s, the concept of a microbiome in humans, animals, and some plants was unknown, although bacteria were part of nutrient cycling. Now we know much more about the need for humans to maintain a microbiome, as well as some food crops. This could become a source of pathogens. While a space habitat can just flush out the agricultural infrastructure and replace it, no such possibility exists for the starship. Crops would need to be kept in isolated compartments to prevent a disease outbreak from destroying all the crops in the ECLSS.
If all this wasn’t difficult enough, the competition asks that the target generation population find a ready-made terrestrial habitat/terraformed environment to slip into on arrival. This presumably was prebuilt by a robotic system that arrived ahead of the crewed starship to build the infrastructure and create the environment ready for the human crew. It is the Mars agricultural problem writ large [10], with no supervision from humans to correct mistakes. If robots could do this on an exoplanet, couldn’t they make terrestrial habitats throughout the solar system?
Heppenheimer assumed that generation ships based on O’Neill habitats would not colonize planets, but rather use the resources of distant stars to build more space habitats, the environment the populations had adapted to [6]. This would maintain the logic of the idea of space habitats being the best place for humanity as well as avoiding all the problems of trying to adapt to living on a living, alien planet. Rather than building space habitats in other star systems, the Hyperion Project relies on the older idea of settling planets, and ensuring at least part of the planet is habitable by the human crew on arrival. This requires some other means of constructing an inhabitable home, whether a limited surface city or terraforming the planet.
Perhaps the main reason why both the teams and evaluators have put more emphasis on the design of the starship as a human social environment is that little work has looked at the problems of maintaining a small population in an artificial environment over 250 years. SciFi novels of generation ships tend to be dystopias. The population fails to maintain its technical skills and falls back to a simpler, almost pretechnological, lifestyle. However, this cannot be allowed in a ship that is not fully self-repairing as hardware will fail. Apart from simple technologies, no Industrial Revolution technology that continues to work has operated without the repair of parts. Our largely solid-state space probes like the Voyagers, now over 45 years old and in interstellar space, would not work reliably for 250 years, even if their failing RTGs were replaced. Mechanical moving parts fail even faster.
While thinking about how we might manage to send crewed colony ships to the stars with the envisaged projections of technologies that may be developed, it seems to me that it is rather premature given the likely start date of such a mission. Our technology will be very different even within decades, obsoleting ideas used in the design. The crews may not be human 1.0, requiring very different resources for the journey. At best, the design ideas for the technology may be like Leonardo Da Vinci’s ideas for flying machines. Da Vinci could not conceive of the technologies we use to avoid moving our meat bodies through space just to communicate with others around the planet.
Why is the population constraint 1000 +/- 500?
Gerry O’Neill’s Island One space colony was designed for 10,000 people, a small town. The BIS Avalon was designed for the same number, using a different configuration that provided the full 1g with lower Coriolis forces. The Hyperion starship constrains the population to 1/10th that number. What is the reason? It is based on the paper by Smith [14] on the genetics and estimated safe population size for a 5-generation starship [125 years at 25 years per generation?]. This was calculated on the expected lower limit of a small population’s genetic diversity with current social structures, potential diseases, etc. This is well below the number generally considered for long-term viable animal populations. However, the calculated size of the genetic bottleneck in our human past is about that size, suggesting that in extremis such a small population can recover, just as we escaped extinction. Therefore it should be sufficient for a multi-generation interstellar journey.
From Hein[14]:
While the smallest figures may work biologically, they are rather precarious for some generations before the population has been allowed to grow. We therefore currently suggest figures with Earth-departing (D1) figures on the order of 1,000 persons.
But do we need this population size? Without resorting to a full seed ship approach with the attendant issues of machine carers raising “tank babies”, can we postulate an approach without assuming future TRL9 ECLSS technology?
As James T Kirk might say: “I changed the conditions of the test competition!”
Suppose we only need a single woman who will bear a child and then age until death, perhaps before 100. The population then would be a newborn baby, the 25-year-old mother, the 50-year-old grandmother, the 75-year-old great-grandmother, and the deceased great-great-grandmother. 3 adults and a newborn. At 20, the child will count as an adult, with a 45-year-old mother, a 70-year-old grandmother, and possibly a 95-year-old great-grandmother, 4 adults. Genetic diversity would be solved from a frozen egg, sperm, and embryo bank of perhaps millions of individual selected genomes. The mother would give birth only to preselected, compatible females using implantation (or only female sperm) to gain pregnancy, to maintain the line of women.
This can easily be done today with minimal genetic engineering and a cell-sorting machine [11]. At the destination, population renewal can begin. The youngest mature woman could bear 10 infants, each separated by 2 years. The fertile female population would rapidly increase 10-fold each generation, creating a million women in 6 generations, about 150 years. Each child would be selected randomly from the stored genetic bank of female sperm or embryos. At some point, males can be phased in to restore the 50:50 ratio. Because we are only supporting 4 women, almost all the recycling for food and air can be discarded, just recycling water. Water recycling for urine and sweat has reached 98% on the ISS, so we can assume that this can be extended to the total water consumption. Using a conservative 98% recycle rate for water (sanitary, drinking, and metabolic), O2 replenishment from water by electrolysis (off-the-shelf kit) and an 80% recycle rate of metabolic carbon dioxide (CO2) to O2 and methane (CH4 by a Sabatier process), implies that the total water storage needs only be 5x the annual consumption. The water would be part of the hull as described by McConnell’s “Spacecoach” concept.
Based on the data in Table 1 above, the total life support would be about 125 MT. The methane could be vented or stored for the lander propulsion fuel. For safety through redundancy, the total number of women population might be raised 10x to 30-40, requiring only 1250 MT total consumables. All this does not require any new ECLSS technology, just enough self-repair, repairable, and recyclable machinery, to maintain the ship’s integrity and functioning. The food would be stored both as frozen or freeze-dried, with the low ambient temperature maintained by radiators exposed to interstellar space. This low mass requires no special nutrient recycling, just water recycling at the efficiency of current technology, O2 recycling using existing technology, and sufficient technology support to ensure any repairs and medical requirements can be handled by the small crew.
Neal Stephenson must have had something like this in mind for the early period of saving and rebuilding the human population in his novel Seveneves when the surviving female population in space was reduced to 7. Having said this, such a low population size even with carefully managed genetic diversity through sperm/ar embryo banks, genetic failure over the 10 generation flight may still occur. Once the population has the resources to increase, the genetic issues may be overcome by the proposed approach.
Table 2. ETHNOPOP simulation showing years to demographic extinction for closed human populations. Bands of people survive longer with larger starting sizes, but these closed populations all eventually become extinct due to demographic (age & sex structure) deficiencies. Source Hein [14]
From table 2 above, even a tiny, natural,human population may survive hundreds of years before extinction. Would the carefully managed starship population fare better, or worse?
Despite this maneuver, there is still a lot of handwavium about the creation of a terrestrial habitable environment at the destination. All the problems of building an ECLSS or biosphere in a zone on the planet or its entirety by terraforming, entirely by a non-human approach, are left to the imagination. As with humans, animals such as birds and mammals require parental nurturing, making any robotic seedship only partially viable for terraforming. If panspermia is the expected technology, this crewed journey may not start for many thousands of years.
But what about social stability?
I do applaud the Hyperion team for requiring a plan for maintaining a stable population for 250 years. The issue of damage to a space habitat in the O’Neill era was somewhat addressed by proponents, mainly through the scale of the habitat and repair times. Major malicious damage by groups was not addressed. There is no period in history that we know of that lasted this long without major wars. The US alone had a devastating Civil War just 164 years ago. The post-WWII peace in Europe guaranteed by the Pax Americana is perhaps the longest period of peace in Europe, albeit its guarantor nation was involved in serious wars in SE Asia, and the Middle East during this period. Humans seem disposed to violence between groups, even within families. I couldn’t say whether even a family of women would refrain from existential violence. Perhaps genetic modification or chemical inhibition in the water supply may be solutions to outbreaks of violence. This is speculation in a subject outside my field of expertise. I hope that the competition discovers a viable solution.
In summary, while it is worthwhile considering how we might tackle human star flight of such duration, there is no evidence that we are even close to solving the issues inherent in maintaining any sort of human star flight of such duration with the earlier-stage technologies and the constraints imposed on the designs by the competition. By the time we can contemplate such flights, technological change will likely have made all the constraints superfluous.
References and Further Reading
Genta, G Genta, “Interstellar Exploration: From Science Fiction to Actual Technology,”” Acta Astronautica Vol. 222 (September 2024), pp. 655-660 https://www.sciencedirect.com/science/article/pii/S0094576524003655?via%3Dihub
Gilster P, (2024) “Science Fiction and the Interstellar Imagination,” Web https://www.centauri-dreams.org/2024/07/17/science-fiction-and-the-interstellar-imagination/
BIS “Project Daedalus” https://en.wikipedia.org/wiki/Project_Daedalus
BIS “Project Icarus” https://en.wikipedia.org/wiki/Project_Icarus_(interstellar)
i4is “Project Hyperion Design Competition” https://www.projecthyperion.org/
Heppenheimer, T. A. (1977). Colonies in space: A Comprehensive and Factual Account of the Prospects for Human Colonization of Space. Harrisburg, PA: Stackpole Books, 1977
Soilleux, R. (2020) “Implications for an Interstellar World-Ship in findings from the BIS SPACE Project” – Principium #30 pp5-15 https://i4is.org/wp-content/uploads/2020/08/Principium30-print-2008311001opt.pdf
Nelson, M., Pechurkin, N. S., Allen, J. P., Somova, L. A., & Gitelson, J. I. (2010). “Closed ecological systems, space life support and biospherics.” In Humana Press eBooks (pp. 517–565). https://doi.org/10.1007/978-1-60327-140-0_11
Hempsell, M (2020), “Colonies and World Ships” JBIS, 73, pp.28-36 (abstract) https://www.researchgate.net/publication/377407466_Colonies_and_World_Ships
Tolley, A. (2023) “MaRMIE: The Martian Regolith Microbiome Inoculation Experiment.” Web https://www.centauri-dreams.org/?s=Marmie
Bio-Rad “S3e Cell Sorter” https://www.bio-rad.com/en-uk/category/cell-sorters?ID=OK1GR1KSY
Allen, J., Nelson, M., & Alling, A. (2003). “The legacy of biosphere 2 for the study of biospherics and closed ecological systems.” Advances in Space Research, 31(7), 1629–1639. https://doi.org/10.1016/s0273-1177(03)00103-0
Smith, C. M. (2014). “Estimation of a genetically viable population for multigenerational interstellar voyaging: Review and data for project Hyperion.” Acta Astronautica, 97, 16–29. https://www.sciencedirect.com/science/article/abs/pii/S0094576513004669
Hein A.M,, et al (2020). “World ships: Feasibility and Rationale” Acta Futura, 12, 75-104, 2020 Web https://arxiv.org/abs/2005.04100
I read all your emails Centauri Dreams emails, but I have to say this is one of the most interesting to date! It was great to see so many of the facts and figures, the challenges and the practicalities discussed in such detail. Thank you. I still have no idea how you manage to find the time to write so many interesting and detailed articles.
(Selfishly, there are also of dozens of potential SF ideas this article has sparked, which I will tuck away for a future date)
Glad you liked the article, Mark, and thanks for your kind words. This one wasn’t mine, though. Alex Tolley is the author. I’m glad to say he’s a frequent contributor.
@Alex Tolley – apologies for missing your byline!
While thanks do indeed go to Alex for yet another manifestation of his extensive and intensive insight in this masterful piece, surely Paul gets credit for continued marshaling of so many – shall we say – “Human Resources”!
Absolutely! I second that! And thanks to Alex too. Extremely thought provoking article.
I recall a novel from 50+ years ago about a generational starship. The ship has been damaged and parts of it are no longer used. Most records about the voyage have been lost and the inhabitants have broken into different factions with various ideas about what their situation is. Unfortunately I can’t recall any more than that…
“Non-Stop”?
Ben Bova story?
The October, 1940 issue of “Amazing Stories” has “The Voyage that Lasted 600 Years” on page 82:
https://archive.org/details/Amazing_Stories_v14n10_1940-10_-_Ziff-Davis/page/n83/mode/2up
1940 was only 85 years ago and not even at the half way point of a 250 year journey,
And hasn’t Western society changed in that time. 250 years ago is about the same time as the colonies fought to liberate themselves from Britain. 90 years later, the US was ending a bloody civil war.
A generation ship that left in 1940 would have avoided WWII and the tumultuous social changes that followed. Would the generation ship’s society change similarly, or would it be fairly static, perhaps constrained by rigid ship rules?
I have ethical problems with generation starships.
So do I. However, we should consider that similar journeys have been taken on Earth with uncertain outcomes for their children. Is a generation ship any worse than living in e.g. Gaza for generations?
I can imagine that a group wanting to escape Earth for some reason and deciding that subjecting generations to life on an inescapable ship was the best option. Is that so very different from the early colonies in the Americas?
Removing children from the tarnished light of imperial Europe was one thing – removing them from Earth, Sun, and the free goods of a vibrant ecosystem is another. Even Gaza might have the land and resources to support millions if no one pollutes the wells, shoots at the farmers, and chops down the olive trees. The ship here is a mere thousand in cramped quarters, with every kilogram of dry food counted up even in the best of times. My feeling is that any child protective services agent to hear this plan would quickly write up one of their own.
I suspect Sedna would make a more realistic generation ship. It will require a lot of thrust, but it has a lot of material to work with. Given suitable fusion technology and a thousand years or so to work on the infrastructure, I think it could be rendered spaceworthy.
The colony habitats in the outer solar system would be similarly, if no so extremely cut off from civilization. Even the largest of the O’Neills, Island 3″ hwas designed for about 1 million people. The richness of a civilization of many billions would be the center of arts, science, and technology. Art and science can at least be transmitted to those habitats. Physical goods might be transmitted for local reproduction or possibly be sent by cargo ship.
A starship would be cut off from the solar civilization, a situation not unlike those utopian colonies on Earth wishing to shuck off the trappings of their contemporary society.
It would be an irreversible commitment with little hope for a return. The Australian penal colony at Botany Bay would be similar for the deported, with no hope of return to England. Their descendants seem to have done OK. ;-)
Starships are like spatial version of one-way time travel. Once you take a trip in either space or time, you cannot expect to return home to the society you left. The children born on a generation would not know of any other life, and after a few generations, there would be no memory of the world they had left, just recordings from that world. We don’t know whether life on a generation ship would be pleasant or not. I would hope that they would be designed to make life interesting for the crew/passengers even within the restriction of the inhabited volume. People who have grown up and lived on small islands seem OK, even if it feels stultifying for a visitor from a city or large country.
A major issue of generational starships that must be addressed at the beginning is education. Assuming there will be children, how will education take place and in what will it consist of? Beyond the natural sciences, social sciences (of a sort), mathematics, and epistemology/philosophy of science, how will these children learn to live with others in the circumscribed circumstances of a starship in transition to a new world upon a later generation arrival? Thus, what kind of ethical and moral education will be necessary? And where, if anywhere, will human history be called upon to provide rooted awareness for spacefarers? Education will be as vital as the air they breathe and food they consume.
I would think there would be more than one craft going out, it also helps to have a wide baseline for communications.
Or have multiple separated hulls. KSR’s Aurora has a separate enclosed ecosystem, and Greg Bear’s Hull Zer Three has separated hulls.
With say three as a number of rotating habitats there would be a lot more redundancy. I would also prefer the rotation to be towards the target star so any impact would hit the thickest part of the craft. Breakages in any parts of the structure could be delt with perhaps floating balloons which move in towards the holes created by any impacts.
What is the expected quality of life for our travelers? Isn’t this the essence of your point?
As I read your comment, I wondered about those poor Gazans, or Somalis, or any other group of suffering folk. What portion of the ‘ideal consumables’ are actually available to any of these populations?
(The question is nothing more than wondering how a lower bound might be calculated, and what assumptions would be included, nothing more.
Alex, Gaza has less population density than Manila, Philippines which has the highest population density in the world with 46,178 persons per square km. They seem to get along fine and don’t attack the neighbours.
Has the Philippines been bombed to ashes, leaving the population with no escape?
My opinion on this is not to attack another country but we are moving into the politics of this area which is very complex to say the least.
It not the uncertain future that makes it unethical. Its that entire generations are being consigned to live their entire lives within the confines of a relatively small space colony (traveling to the stars). But your other points are valid.
In any case, I’d rather do it when we have radical life extension coupled with some kind of hibernation or truly reversible suspended animation. That way, the people who set out on the journey at least get the benefit of actually enjoying their new lives on the new world.
Assuming that FTL is impossible (a reasonable assumption in my opinion), we will be building and living in large-scale O-neill style habitats long before we go to the stars. Since people are used to living in space with living on planetary surfaces going out of vogue, people will simply go to the nearest next star, regardless of what planets it has, and build new habitats there.
Speaking of SF, it interesting that SF is full of FTL but rarely features the development of super-strong exotic materials that would allow for construction of Banks orbitals and other such megastructures. Afterall Star Trek does not feature megastructures. Then again, it has to remain consistent with its 1960’s original series roots.
I do as well, I am not sure I could stomach sending those untold children on a one-way trip, its to much like a jail with so little freedom of choice.
@J Sheppard
It would be more comfortable than living in a family nuclear shelter for decades, or wandering the desert for 40 years with Moses, or being forced to walk from tribal lands to relocate to a reservation in very different environments. Living life in a slum or ghetto might be worse. Life imprisonment with no parole is worse, especially if the only way for a child to survive is with the parent.
I have lived on a small island for a couple of years. While I got “island fever” I noticed that I progressively reduced my journeys to avoid the equivalent of pacing a cage. Many people seem quite content with such a life. Village life in the age before safe and cheap travel was very similar.
Therefore, a ship with lots of interior volume, pleasant surroundings, and all the comforts of modern society, might be rather preferable to many existing conditions. Just because it is hard-bounded doesn’t mean that it is mentally confining. If one needs the experience of wandering, perhaps VR (or “holodeck”) is the solution.
I also have ethical complaints about generation ships whose goal is to colonize a planet that is already suitable and probably already has life on it, otherwise it probably woudn’t be suitable for us. To me it seems like a step backwards to plunk ourselves down on another deep gravity well that can’t escape it’s own eventual destruction.
I think rotatiing space colonies that don’t need to be self sufficient are the way to go. There are plenty of resources available throughout our own solar system that can be mined to replace any that are lost in the colony. Gradually building and moving the colonies outward from our planet, even into the oort cloud and beyond (as long as resources are available) makes more sense to me. Moving outward toward the stars at a leisurely pace, finding systems that have no life in them and using those resources seems more logical to me. These colonies would look a lot like a generation ship without the pressure of having to be a closed system and without the risk of impacts while moving at high velocity toward a distant star.
We can leave the other planets alone to evolve (or not) and not risk stopping their evolution in order for us to continue with our medieval idea of colonization. Would we want to colonize a planet with complex life of any kind already in place? Nothing would stop us from doing it, assuming we had the technology, but do we not have any moral compass telling us not to?
I suppose if the oxygenic organisms in the distance past had a moral compass the methanogens would still be in control. Now since we are more intelligent i would think we should keep away from those that have life on them already. However an oxygen rich atmosphere planet may be a jewel too bright to ignore and would most likely have life already on it.
“I think [rotating] space colonies that don’t need to be self sufficient are the way to go. . . . .”
Yeah, I’m curious to see, overall as to all these planetary destinations and other fixed g level gravity wells inside and outside of the solar system, how the at least current human organism and genome will function in and adapt over time trying to live permanently in less than 1 g.
Like in the case of .38 g on Mars, following also an extended possibly micro-gravity flight over.
Every time I try to do lay research on that, I just run into more of that handwavium to which Alex refers. (Perhaps in the same part of the periodic table with unobtanium.)
The O’Neill cylinders that you indirectly reference – if otherwise feasible – do seem to get around that issue by creating a 1 g environment wherever we go. (Outside of having a city-state floating in the Venusian clouds at also approximately 1 g.)
All that said, I am indeed working now – as in that’s what I roll out of bed and work on basically every day these days – on that draft proposed constitution for a Mars settlement to which I referred a while back. It’s drafted currently specifically for Mars because that looks like the first place that we’re going. But, with minimal adaptation, it could serve as a constitution also for a settlement placed instead in a structure in an at least more or less fixed location in open space (i.e, of course orbiting the Sun and/or some other celestial body). That is my intent anyway.
A generational starship . . . well “that might be a different matter” in terms of a structure of governance. On the one hand, it’s essentially a long duration mission full of risks where an established and hierarchical mission command structure might seem necessary, especially at those times when the stuff is hitting the fan. On the other, you’re going to maintain that rigidity and to some extent constrained individual freedom for . . . ten . . . generations? Without something like a unitary theocracy or outright cult to (try to) keep ten generations of the flock all believin’ as they’re “bringing in the sheaves” each generation? For a future period of time longer than the U.S. Constitution currently has been in existence? Related to the ethical issue raised, later generations may well go “hey, I didn’t sign on for this . . . you ain’t . . . my . . . commander.”
Of course, that to an extent is true for every succeeding generation born into a preexisting form of governance. But one can imagine the generational starship context putting “a bit” more societal stress into the mix, with stresses accumulating on both the craft and its occupants. Makes that line from “Hotel California” all the more apt, as you truly can never leave, for all but the last generations.
And it’s of course a pretty sizable “two-leg parlay” to bet that the destination still will be there, at least in a then habitable form, when the ship gets there. Things happen, like asteroid collisions and/or terraforming failing and/or being wrong about what life, possibly even sentient life, already is there, or maybe gets there before you do.
I sometimes suspect that irony may be at the very heart of that unified field theory that they keep trying to develop in physics.
Anyway, for Mars, the proposed constitution itself is about 99.7% complete, in a stem to stern draft, but with some minor revision here and there likely still to come. The heaviest lifting that remains, as it did when I shelved the overall project years back, is in the “explainer” and/or “influencer” essays that function similarly to The Federalist Papers from the late 1780’s.
I’m trying to complete all, or at least enough of those essays for the moment, by around the end of June. To then all be put – it’s a lot of content, with the proposed constitution and the essays – on a standalone website. And then my plan is to, inter alia, submit for Paul’s review the first of a possible Mars series of cover articles addressing larger themes about the then-linked proposal.
But, yeah, SpaceX currently has the political winds figuratively at its back – at least for the moment – vis-à-vis going to Mars. And they’re doing flight testing and development on the craft that they intend to use to get there. As well as to ferry settlers down the line.
So “it seemed like it might be a good time” to complete the project.
We’ll see – still a lot of writing to go. But “I am on the case” and working toward a specific target deadline.
@George,
The USA is a live demonstration of what was thought of as a model constitution being torn apart at the seams, once in the 19th century, and again now.
Mars will be a very young nation. It might well fall into despotism quite quickly. The lack of breathable air is an effective pressure point to suppress a population. Any constitution, laws to adjudicate unforeseen ambiguities, guaranteed, independent law enforcement, and a way to prevent bad faith actors from usurping the laws to take control.
You have a lot of work to make it “bulletproof”. Good luck.
Thanks, Alex, some luck definitely will be needed, here and then on Mars.
That risk of despotism is part of why I believe that the very first permanent settlers should adopt a constitution from sol one, circumstances permitting (such as the settlement not being simply a “company town” run by on- and/or off-world corporate interests).
Establish the settlement’s political autonomy (within the constraints of current Terran treaty law), basically democratic rule, and individual freedom from the get go. So that they don’t have to try and ask for it later (speaking of luck then being needed), or instead have to have their own 1776 moment.
SpaceX bringing the transport costs down likely will allow the settlers to get there.
But, if so, that also will allow others that more or less copy the SpaceX innovations to also settle on Mars who may be wholly antithetical to the settlers’ desired political autonomy, democratic rule, and individual liberty.
Not to mention competing over access to the best resources and settlement locations on the planet as well as to resources in other comparatively accessible places like the asteroid belt.
So the settlers may well find themselves in very much a comparable situation to the early United States, both internally as well as being only a nascent political entity in the midst of a highly competitive external situation.
But vigilance always is required to stay free – both in domestic politics and vis-à-vis external interests.
Ultimately, regardless of what’s written, but one does try to craft the words to give them the best shot at it.
“I am indeed working now – as in that’s what I roll out of bed and work on basically every day these days – on that draft proposed constitution for a Mars settlement”
I was totally enthralled by KSR’s in-depth writing on this very subject, contained, I think, in Blue Mars. He does tend to go on, and on, and…but it’s thoughtful and politic and I look forward to reading your take at some point. What on earth motivates a person to tackle such a Herculean task? 😀
thanks, Michael . . . I can go on and on and . . . , too, lol. Or at least that’s what my Brit ex would say.
The project reminds me of the 2010 movie Inception, where a simple core idea takes hold and then grows exponentially in someone’s mind, like those extensive dream cities the architecturally-inclined characters in the movie would create in their subconscious minds.
So, yeah, it just got started after I looked around back somewhere before 2014 and wasn’t satisfied with the efforts at drafting a proposed Martian constitution that I saw then . . . and the idea took on a life of its own thereafter. I typically roll out of bed currently with specific content in mind, courtesy of that subconscious like in the movie.
And I still haven’t seen anything yet since then that might cause me to stand down and go “ok, that’ll work, never mind about my draft.”
I have seen in digging around again recently that Professor Charles S. Cockell, a professor of astrobiology at the University of Edinburgh and the British Interplanetary Society each were involved in similar – perhaps to an extent interrelated – efforts back in the mid to late twenty-teens. And SpaceX reportedly hired a gaggle of space lawyers (it has become a specialty) to draft a Martian constitution a couple of years back.
But I haven’t been able to put my hand on any final product from any of those efforts. That’s a rabbit hole I plan to run back down again in or after June after I’ve reached a better stopping point, including contacting the British and maybe SpaceX folk directly if necessary.
But, yes, it is a fairly involved task, which is why it got set aside at one point or another over the years.
And it might have stayed on a side or back burner for a while longer if the particular political winds pertaining specifically to Mars (trying to keep the reference to politics tightly cabined to the topic at hand) were blowing differently.
But the discussion these days centers around specific upcoming Mars transfer windows for the initial uncrewed and then crewed missions, so we seem to be getting close. Closer than we’ve been in a while, especially in terms of transport costs.
@George King – the modern constitutional projects I’ve looked at keep turning out to be bitter disappointments. Their first instinct is to water down the critical pillars, notably freedom of speech, while failing to embrace even simple common-sense reforms like ranked choice voting.
@Alex – the failures of the US constitution seem mostly attributable to two peculiar institutions. 1) slavery, where some people are property all of the time, and 2) intellectual property, where all people are property some of the time. We’ve seen how expansive, almost fundamentalistic applications of “IP” to business models and software algorithms has created single-company industries, and how the domination of content by a few players left the public to be shaken like ants in a jar by a handful of media owners. What Lenin would have called “moribund capitalism” doesn’t really seem that different from state communism, apart from who the bosses are and what clothes they wear.
A proposed constitution might benefit from input from a variety of sources, notably Chinese sources now that they are the rising superpower. The success of that country might trace to other kinds of useful principles, perhaps notably the Confucian tradition of standardized testing for civil service, which differs so notably from the appointments we see in the U.S. nowadays. A constitution may also need to focus on ‘positive rights’ – the right to the essentials of life, no matter how one fares in the economic game. This is particularly relevant where air is not free! Last but not least, China has suggested principles of management democracy and workplace democracy which could be explored to change the behavior of corporations. Creating artificial people who can declare bankruptcy but pay huge salaries to a few officers in charge… that isn’t really a law of nature, is it?
The central problem of democracy is the creation of a free and fair forum – so everyone can be heard and the best ideas can spread by a sort of natural selection. The central problem of capitalism is the creation of a free and fair marketplace – so everyone can work hard and do well and get ahead and make their superior products available more widely. Maybe the central problem of socialism is the creation of a free and fair system of public support – so that people can rest at a basic level and have room to think, study, learn and experiment to solve the problems the market will not.
But I don’t think a Musk Mars is going to be any of these things. The greatest anarcho-corporate utopia in history was the International Association of the Congo. I think HIV started there when the same machetes used to cut rubber and bush meat were used to collect quotas of hands. I doubt having a private company effectively running a closed camp that people can’t leave will go well today either, especially when the owner is the world leader in brain implant chips.
The only quibble I have is your statement:
IIRC, China’s earlier societies only allowed such civil servants from elite families. It was certainly not meritocratic.
source: “Pre-Industrial Societies” by Patricia Crone.
As a product of the “Western Enlightenment”, I would most definitely not wish to live under one-party rule that is totalitarian. That applies to both communism and fascism.
This is still relevant:
“It has been said that democracy is the worst form of Government except all those other forms that have been tried from time to time”
― Winston S. Churchill.
I am also reminded that the EU’s constitution was over 700 pages! One failing is that a single representative country can block decisions that the rest of the union agrees to. Hungary is the current example.
@Alex – This site tells it differently. Note I’m not suggesting a retreat from democratic principles, but choosing between two primary candidates emerging from opaque party and media processes has only limited potential to prevent disaster. China’s successes indicate that there must be alternative structural safeguards which can contribute to the overall success of a manufactured constitutional system.
“I sometimes suspect that irony may be at the very heart of that unified field theory that they keep trying to develop in physics.”
Please explain what you mean by this George.
Just a tongue in cheek remark said with a smirk.
As in, for that cat, the outcome as between the two possibilities, in any reality, perhaps will be the one that is most ironic.
I mean, existence itself – at its most fundamental level – gets rather ephemeral the closer we look at it.
Existence behaving differently – or, well, at least definitively – when it’s being observed rather than not.
Particles bubbling into and out of existence in otherwise empty space.
As if it all indeed were just a passing thought in someone’s mind, at the edge of a dream.
Someone with perhaps a rather acute sense of irony . . . .
Got it, thanks for elaborating further.
The Universe is indeed a very strange place!
Well, I suspect that a planet with life already on it would be a toxic-poison nightmare for humans!
Not a great target destination.
Just briefly breathing in air laden with particles of different arrangement of amino acids / protein patterns would likely be quickly deadly.
And how long before an alien fungal analog takes a real liking to your warm moist lungs or digestive tract–the way fungi on earth rapidly learn to colonize anything–even nuclear-rods at power stations!
And then the possibilities of predators.
Or imagine the air permeated with a bio chemical similar in toxcicity to humans as say botulism compound?
Thus rather than flock to planets with alien life for colonization, humans might avoid them like the plague!
They are the worse place you could think of to colonize.
Instead: a nice barren, no atmosphere, mars like target would be much better since adding an atmosphere would be far easier than dealing with countless/endless trillions of bioactive alien particles and chemicals all over everything.
On a tangent note:
Were we to ever detect intelligent alien life, I’m not sure we could ever physically meet each other in the same room safely without running a high risk of accidentally poisoning each other via the endless stream of microparticles living creatures emit constantly.
The release of ancient bacteria and viruses is happening now as the tundra warms and revives this biota.
What if warming Mars as part of a terraforming operation does the same should ancient life have been present on Mars? Even if it wasn’t, we know Martian rocks have landed on Earth. This suggests that terrestrial rocks might similarly end up on Mars. If these rocks carried terrestrial organisms from our past, could they become a problem for Martian settlers as water is extracted from subsurface glaciers?
Maybe a magical Star Trek “Genesis Device” needs to be used. Better than nuking the planet from orbit – “the only way to be sure”. ;-)
When some of us crossed the Bering Land Bridge so many moons ago, we had neither the knowledge nor the compunctions eliciting any hesitation to proceed.
I’m old enough to remember when we thought planets were rare and terrestrial planets even rarer (but asteroid and kuiper belts common) and those of us in L-5 Society responded with the retort that we don’t need no stinkin’ planets.
I personally don’t think it will be 250 years because as our solar system gets more infrastructure we can transmit more power and faster craft later on. For instance we could send the main craft on at a set speed but later on we could send some large lens structures out which trail behind it which we can then transmit laser/kinetic power to speed it up or slow it down on arrival.
The 250 years is the i4is’ competition constraint. Whether it is 250 years experienced time or real time is also an issue.
If we could beam ourselves to a target planet, experienced time would be 0. That would make interstellar travel easy for the individual, but of course the a long time may have passed in the universe.
We really have no idea whether there will be starships of any kind, and whether they will be fast or slow if there are.
IMO, biological beings will not be the crew, but rather robots that can simply power down during the journey and power up on arrival, avoiding biological ageing and senescence.
I think this is right. These aren’t really people getting on board a ship to have their descendants get off on a planet – they’re folks in their own habitat detaching from the solar system infrastructure so they can build a new set of it at the destination, with the habitat becoming part of it.
They won’t try the generation ship route if they can’t make a habitat self-sufficient and resilient enough against leaks first just for living back in the solar system. They’d opt for faster speed instead, or simply live the entire trip with advanced medical science and longevity increases.
One potential solution to the challenges associated with generation ships involves advancing our understanding of the biophysics of aging and utilizing genetic engineering. By combining these advances with cloning, artificial intelligence, and robotics, we could make a 250-year journey feasible.
Alternatively, another approach could be to transport eggs and sperm to establish a genetically diverse population upon arrival at the destination. This strategy may also be more cost-effective, as it would enable the construction of hundreds of ships with only a small crew on each. This arrangement would better account for unforeseen circumstances during the voyage. If a ship encounters major issues, the crew could transfer to another vessel, allowing the damaged ship to be dismantled for parts to support the others.
Interesting update on light sails.
Pentagonal photonic crystal mirrors: scalable lightsails with enhanced acceleration via neural topology optimization.
https://www.nature.com/articles/s41467-025-57749-y
The Starshot Breakthrough Initiative aims to send gram-scale microchip probes to Alpha Centauri within 20 years, propelled by laser-driven lightsails at a fifth of light speed. This mission demands innovative lightsail materials with meter-scale dimensions, nanoscale thickness, and billions of nanoscale holes for enhanced reflectivity and reduced mass. Unlike the microchip payload, lightsail fabrication requires breakthroughs in optics, materials science, and structural engineering. Our study uses neural topology optimization, revealing a novel pentagonal lattice-based photonic crystal (PhC) reflector. The optimized designs significantly lower the acceleration times and, thereby, launch cost. Crucially, they also enabled orders-of-magnitude fabrication cost reduction. We fabricated a 60 × 60 mm2, 200 nm thick reflector with over a billion nanoscale features, achieving a 9000-fold cost reduction per m2. This represents the highest aspect ratio nanophotonic element to date. While stringent requirements remain for lightsails, scalable, cost-effective nanophotonics present promising solutions for next-generation space exploration.
Diamond makes a great material as well, not sure of the costs though. A quick calculation is that it was exposed to 22 GW for 30 seconds and had no visible damage !
https://www.researchgate.net/publication/360523015_Diamond_mirrors_for_high-power_continuous-wave_lasers
Size of diamonds on Uranus and Neptune
Opps that is 22 GW per square meter and if we had a bit of this material in a 1 square meter and 1 g format and exposed to this illumination it would be accelerated at around 14 000 g.
The issue of making a world inhabitable for humans was addressed in the previous post, but is raised again by the assumptions for the Hyperion Project competition.
Clearly, a generation ship needs a destination. As I state in the OP, rather than have the arriving generation build space habitats, the i4is team assumes that either the planet is ready for colonization, or that some area is made ready, with or without some isolating membrane.
Let’s suppose there is a closely biocompatible world that has all the ingredients for human habitability, like the planet Zyra at the end of “When Worlds Collide”. But suppose that the conditions are not sufficiently Earth-like and the colonists decide to make it closer to Earth’s conditions. This may then upset the current evolutionary adapted life on the planet, causing the slow extinction of species. This is not unlike the effect of human activity on Earth – reducing habits, polluting the environment, introducing invasive species, etc. Should the generation ship’s target generation make those changes to survive and reproduce to create a new civilization? Unless the starship has access to the manufacturing needed infrastructure to start a new voyage to another star, the crew is stuck in the new system. The moral dilemma is repeated, but with fewer choices. The starship will unlikely be able to maintain the crew, and if it does, the population cannot increase. Therefore, will the need to survive overcome any moral concerns over the extant life on the planet? [History suggests the answer is yes.]
None of this is considered in the competition for obvious reasons. But IRL, should we eventually build such colony ships, shouldn’t these questions be resolved first before an advance party is sent to prepare the destination for the generation ship? If so, this might be a good case for sending a robot ship first. But would an AI allow its self-sacrifice if its analysis suggested that a human colony would eventually destroy much of the extant life?
With our available current database on exoplanets, I don’t think we have a candidate destination that would be any more attractive than Mars is, unless, say, Trappist 1 or another system suddenly shapes up after all to have an atmosphere and radiation shielding better than such. It appears that from what we know today, terra-forming would be at least as challenging for known HZ exoplanets as the majority of objects of the solar system, assuming homesteading for a later generation is the objective of the flight.
On the other hand, were we to discover a living planet with life on it, it would be a threshold for human exploration. But the above concerns about justification at destination for a quarter millennium flight seem right on. It could well be that the
advances in sensors such as space telescopes could outpace such an expedition in scientific returns for viewing exobiology, whatever it entails.
Survival in such a planetary environment poses dilemmas such as risk to what makes human survival possible – the exobiology, whatever it entails.
Given that, a robotic sanitized precursor mission at higher speed might make more sense to avoid disaster for a future generation ship crew or the destination.
The exercise does appear to isolate from each other the payload and the spacecraft capable of 250 year duration flight. But we don’t know how far this spacecraft has to go to reach its destination. As target distances in light years increase, the 250 year design point becomes less and less feasible. Depending on how exoplanet information continues to filter in, we might end up with a target exoplanet out 25 light years ( UGLY) vs. another at 50 ( better). But the flight velocity for respective cases would be 0.1 and 0.2 c. The nearest case Alpha Centauri (< 5 light years.) would 0.02. Then there is acceleration and braking.
Granted that our capability to detect exoplanets is more like sampling than thorough screening. There might be more good candidates nearby than we now know. But we need to identify better ones than we have thus far to recruit anyone ( families!) for a 250 year voyage. Recruiting pioneers on the basis of a planet having elements that stand as the basis of biochemistry – or simply that they appear in the periodic table. Polynesian migrations, for example, were arduous enough, but Pacific islands ( at least substantial numbers) had some prospects if seafarers could locate them.
In fact (?), an alternate might be another look at suspended animation. I don't think I have the capability in my genes. But maybe future generations can opt for something like it. At that, I am not sure what mammals on Earth can be suspended for the periods such as required. But that might be an initial line of research.
My take on a couple of the above.
I think it would be evil to colonize another viable ecosystem.Just my opinion.
I don’t think it would be evil to make a decision that will drag your children along with you , happens every day.
People talk a lot about the hardships but given the tech I don’t see why the passengers wouldn’t live a safer, healthier , more comfortable existence than many billions of individuals on earth have before now.
It’s obvious that many problems will have to be solved, but the same is true of starshot which has many fans here.
Generation Ships
I appreciate the article; I too used to read some novels with generation ships and I can imagine using them. I like the idea of choosing a suitable asteroid, hollowing it out some and installing a cylinder to rotate to provide gravity. A “suitable” asteroid would have water ice and be composed of every necessary kind of mineral. It would provide resources and a radiation shield and perhaps even disguise. Of course it would have immense inertia so it would need a Lot of energy; technology to be developed.
After hollowing out the initial cylinder room additional tunneling for resources and room (for a slowly growing population) would be done en route, providing motivation to stay developed.
Of course the suitable asteroids might be limited in number and only grudgingly made available but it would have the advantage of being able to go on if the target system didn’t work out.
Just musing over the idea that terra-forming robotics would be sent out in advance. So, we are going to say 250 years for them to get to a suitable exo-planet? Shall we then say only 50 years for the initial proof of concept that would give us the confidence to launch a crewed ship? Who among us imagines that any human society could/would maintain and finance the 300 year long project to terra form a destination, even if the first try worked?
So yeah, we would have to send out a number of terra forming robotic teams in order to increase the confidence of finding a suitable destination. And, some destinations are further away. So let’s say for discussion 350 years and 3 times the money needed to find out if there is a successful terra form underway?
Yeah, I’m not too hopeful…
@Benjamin
And yet past societies have expended generations building projects, such as cathedrals. One could argue that the USA has spent 250 years trying to build a Democracy that lived up to the founders’ ideals that are expounded in the US Constitution and Bill of Rights.
Our rapidly changing modern society has shortened attention spans, which has become detrimental to dealing with longer term threats.
Dear Alex,
Thank you very much for this well-researched and thoughtful article. When I founded Project Hyperion in 2011, the goal was to do for generation ships what Project Daedalus did for interstellar probes. To stimulate thinking on this topic and to more exactly pinpoint the potential issues that such a mission would need to address.
Regarding the competition, we had to create a “sandbox” that allows teams to come up with designs within a short timeframe. Hence, some of the constraints you mentioned, such as the existing ecosystem on the exoplanet, had to be put in place to restrict the design space to a reasonable size (“sandbox” idea).
@Andreas
I fully understood why you needed a constraining sandbox. What would be helpful is for you to explain why there was no requirement for anyone with biological/agricultural knowledge on the competitor teams, nor the judges. As I stated in the OP, it implied that you considered ECLSS a “solved problem” which I think I explained it is not.
While you have provided some support for the population size in various prior work, could you critique my suggestion for a very small, all-female generational crew, with minimal technological requirements for storing all the needed food and recycling water and air using existing technology? I want some serious pushback on my suggestion.
This discussion would be a lot different if ageing was solved
i.e. we moved from a life expectancy of 80 years to a life expectancy of 1000 years
@Steve,
Or that we could propel a ship at high fractional c for relativistic time dilation. Or that suspended animation was possible.
However, longevity is best achieved using a non-biological “crew”. If we can design such entities to last 250 years (perhaps transferring “minds” into newly built “bodies” if needed), then this solves the problem for explorers and colonizers, just not [post] human ones.
Maybe someone should design a computer game around generation ships: useful ideas may flow from playing it.
Here’s a good video roundup on the issues faced with these multigeneration interstellar ships:
https://www.youtube.com/watch?v=r4sYJfPw0Rk
Until effective space radiation mitigation issues are worked out, no one will most likely survive the trip. It’s a big question mark at the moment if Nuclear Fusion Propulsion is feasible in practice. Also if artificial gravity is feasible without using rotating structures (in microgravity) this will significantly change the ship design.
Perhaps we could every now and then shut down a ship and refurb it, i.e. change the entire interior to prevent boredom.
Or the ship could do that itself, like a puzzle box mystery? But bear in mind, some people prefer things to stay the same. The older one gets, the less one likes change, too. Perhaps some parts of the interior remain static, whilst other parts change. If there are any “natural” areas, then growth and organism change can occur with ecological succession.
I am surprised that the subject of group psychology is not addressed in this situation of confinement and travel without return. I think that the first two generations will be essential for the survival of the group and the mission, in the sense or not only they will have to bear the psychological shock of their rupture with the cradle earth – even with some training it will be difficult – but also educate their offspring (to pass on the culture of knowledge but also the objective of the mission) while maintaining a leadership role to maintain the cohesion of the group; which will be particularly difficult over time in such a context.
It is known that psychological disorders sometimes serious after a few weeks in individuals locked together in a closed environment (submarine; polar confinement experience; 1st space flight) What will happen in the group when all the landmarks that the human species has known for ever – earth; moon; sun – have disappeared?
It is already difficult to make an effective two-man of commandant binomial in an airliner due to a multiplicity of human factors. “Efficient” means that is able to lead the plane from a point A to B without problems, to interact with the instruments of edges and therefore also to preserve the group-passengers while keeping this role of leader. I am thinking of N. Armstrong and his reaction ability to restart the LEM …with his pen; to Cdt Sullenberger but one could also cite inombrables examples of military situations with rapid decision making. What will happen in our ship ? no one really knows…
If the 1st generation is not able to maintain the cohesion of the group and, for example, falls into madness, the rest of the mission will necessarily be impacted. either because there will be conflicts that will persist in generations or groups will have divided (as in “non-stop”) which over time risks to lose the goal of the mission to future generation. the greatest difficulty will be to maintain and transmit knowledge and culture which is inherent in the survival of a species.
Passing on knowledge and giving a purpose to the group is essential. here the difficulty will be to pass it on through the generations in time. Without the transfer of experience, there is no evolution. What would happen if the 10th generation had become “wild” or no longer knew about the purpose of their journey and mission? What would she do in front of the terraformed exoplanet for her? it’s a nightmarish vision for the poor descendants. Certainly there would be computers that could remind them why they are in there, but would they still trust the computer even if they had known only it ? In short: how will the N+10 generation adapt to interstellar space? one can only speculate
It is the environment that will partly condition the group: do we need private spaces or all in common? Should they be identical and standardized to avoid conflicts – one is always jealous of his neighbor – or created according to the social role of each? (Should the leader have more? ) Our architects have already broken their teeth on these subjects: think of the Soviet community apartments; intensive urbanization; to Le Corbusier who could have driven any guy who lived in his “boxes” crazy;)
While we may be able to handle technology on the whole, the human problems are considerable, essentially because the cradle of the human species will be transposed: its vessel will be its planet for 250 years. Note that once again we find the idea that Man wants to play God and create his own world ;)
now, let’s forget our ethics and turn the problem upside down: rather than adapting the vessel to the individual, shouldn’t we adapt the individual via bio-technologies? which would mean totally modifying the structure of this society, based on morality. is it worth it? I’ll leave you to play Dr. Frankenstein…
@Fred
I hope Andreas Hein (or one of the i41s HP judges read your comment when they evaluate the “social design” for the generation ship.
Have you by any chance seen the film On the Silver Globe? It is supposedly a cult movie (although I didn’t like it at all). It has astronauts arrive on a planet and give birth to a new civilization. The astronauts are much longer lived than their wild offspring so they can see changes that occur. It may appeal to your more sociological POV.