Generation ship design project

[terrafamilia]

FYI

https://www.projecthyperion.org/

Project Hyperion works on a preliminary study that defines integrated concepts for a crewed interstellar starship or generation ship. The study aims to provide an assessment of the feasibility of crewed interstellar flight using current and near-future technologies. It also aims to guide future research and technology development plans as well as to inform the public about crewed interstellar travel.

They are focusing on the habitat, including landscape, dwellings/buildings, knowledge base and society. All the technical systems are outside the scope of the competition.
Winners are expected to be announced next June.

Ciao,

Terrafamilia

[stevebowers]

The design of the habitat and buildings is much less important than the 'technical systems', especially the ecological life support systems and the acceleration and deceleration systems. If you can't accelerate the payload or maintain the ecology you'll never get there, no matter how well your environment is designed.

[Rynn]

The design of the habitat and buildings is much less important than the 'technical systems', especially the ecological life support systems and the acceleration and deceleration systems. If you can't accelerate the payload or maintain the ecology you'll never get there, no matter how well your environment is designed.

Not to mention the needed design of the economy to ensure there are sufficient workers and industrial complexity/capacity for a closed system. Plus the social institutions that would be needed to ensure the delicate ecosystem/economy in a bubble survives without some conflict causing it all to crash down.

[Drashner1]

Looking at the website, it's honestly not clear to me what they are actually asking for, although my best guess is an exercise in imaginative architecture. The wording is vague and imprecise. Downloading the proposal document they say the ship should have a 250yr flight time with a crew of 1000 +/- 500 (which is at least an order of magnitude smaller than what OA presumes is used for its early interstellar colony missions). They mention ship systems in a general way but its not clear if these are to be considered or mentioned or if they are just looking for pretty building/habitat designs (those aren't to be discounted, but I think it gets iffy on how to do this if you aren't clear on what the tech level is. There is mention of 'near future' tech and some kind of 'tech level 2' apparently referencing some other guideline or book or whatnot.

They do want an engineer as part of the design teams, as well as some sort of social scientist and there is reference to the social structure (presumably including the economy) of the ship.

I suppose it might be worth keeping an eye on to see what kind of cool images might come out of it but I don't know that this is going to provide any particularly new insights for us from a worldbuilding perspective.

My 2c worth,

Todd

[stevebowers]

1500 people on a 250 year mission? If the ship was going to Tau Ceti the speed would need to be 0.047c - quite a respectable speed. In OA it would probably be a sleeper ship, and the payload would be significantly smaller. But if we imagine it was a generation ship it would require a lot of energy to get up to that speed, so the ship have massive propulsion system, probably both rockets and a drivesail.

Obviously the agricultural sections would need to rotate for internal gravity, which would mean a large drum-like section - perhaps two rotating in different directions to even out the angular momentum. If the ship decelerates these segments on arrival they could be used as a habitat in the new system - or, alternately, a more efficient use of energy would be to decelerate a much smaller segment of the ship using a magbrake, then arrive into the system in a smallish, cramped vessel and hope that the occupants of the ship could quickly acquire enough resources in the new system to survive. A tricky proposition, but it is always more efficient to decelerate a small payload than a large one.

Maybe the generation ship would be preceded by a fleet of smaller robot ships that help to gather resources for this eventual arrival, but these robot ships would need to be almost completely autonomous because they would be separated from the ship's crew by light travel time, and any new instructions would take years, months or weeks to arrive (assuming the robot fleet was controlled by the generation ship's crew as it approached). This is not really current or near-future technology. But if it worked, the ship would arrive at its destination to find a preconstructed habitat waiting for them.

So the mission plan I would propose is a large, relatively slow generation ship with two or four large counter-rotating agricultural rings growing food for the journey, with a central, smaller ship at the hub intended for the two-year deceleration phase. This would be accompanied by a fleet of smaller unmanned largely autonomous ships that construct a habitat at the destination - probably from asteroid material including water ice and rock. The counter-rotating rings would then become redundant and would be discarded just before deceleration- perhaps some, or most, of the mass could be converted into propellant to assist in the deceleration, but that might require some pretty weighty machinery (which would reduce the efficiency of the process).

Before we could attempt such a mission we'd need very good closed ecological life support system technology, and very good automated robot systems, and a sustainable and largely automated education/training system that would ensure the crew/colonists could be trained in all the necessary skills to maintain the ship (and the colony at the destination). I don't think this would be possible without competent general artificial intelligence and a comprehensive database, so we won't be attempting anything like this in the next century or two.

And of course my proposal would only work if everything performed its function flawlessly - if the robot ships couldn't create a sustainable habitat at the destination, the people in the ship would probably starve to death on arrival. And so on.

[Rynn]

And of course my proposal would only work if everything performed its function flawlessly - if the robot ships couldn't create a sustainable habitat at the destination, the people in the ship would probably starve to death on arrival. And so on.

IMO the "ship" in "generation ship" is a misnomer. Core to the idea of a generation ship is that you have an industrial economy sufficient to maintain a transplanted biosphere sufficient to sustain a population large enough to work the economy, all within a closed system. That's not a ship, that's a mobile habitat. Hell a better mental framework would be a mobile, closed, city-state.

Nothing like that should require that the inhabitants build a habitat as quickly as possible on the far side. An ark of this kind would be more than capable of continuing to act as the habitat it always has while the citizens work to gather fresh resources for the first time in generations.

But yeah, the real kicker is less the rocket science (that's the trivially easy part, relatively speaking. and more the design of social, economic, ecological systems to survive centuries in a closed system. Asking how to design a generation ship is little different to asking "how can we create a sealed underground city that, when we open the doors in a few centuries, still has a thriving population".

[stevebowers]

IMO the "ship" in "generation ship" is a misnomer. Core to the idea of a generation ship is that you have an industrial economy sufficient to maintain a transplanted biosphere sufficient to sustain a population large enough to work the economy, all within a closed system. That's not a ship, that's a mobile habitat. Hell a better mental framework would be a mobile, closed, city-state.

Nothing like that should require that the inhabitants build a habitat as quickly as possible on the far side. An ark of this kind would be more than capable of continuing to act as the habitat it always has while the citizens work to gather fresh resources for the first time in generations.

That's the concept behind a true generation ship, certainly. The best use of this concept is to reduce the speed significantly in order to reduce the amount of propulsive energy required; every time you double the speed, you square the required energy (at least). But a longer journey time, measured in thousands, rather than hundreds, of years, makes it more likely that the closed ecology will fail en route.

That's why I prefer quasi-generational ships, that use as much stored information, autonomous equipment, discarded mass and miniaturisation as feasible; they can arrive quite a bit faster and are less likely to fail. They also need more advanced technology, and more propulsive power.

[Drashner1]

Truth be told, the full range of technology (in all the gritty details that would need to be addressed) required for interstellar travel leads me to think that such is so far beyond our current abilities that any guesses as to how a starship would actually work are either just WAGs or attempts to create enthusiasm or 'sensawonda' rather than serious attempts at design.

Making a closed ecosystem or life support system that can function for anywhere from decades to millennia inside a structure that is only a tiny fraction of the size of a planetary surface is something I don't think we have even the faintest idea how to do. At least I've seen nothing/next to nothing in the way of writings about it in all my metaphorical travels.

This is not to say such is impossible or that we won't ever do it or won't do it for thousands of years. Just that there are a huge number of details that most authors don't even begin to touch on and the level of know how required is so distant from current state of the art that we can't predict with any confidence when it will become possible (IMO).

Todd