Author Topic: Worldships  (Read 6993 times)

Offline lamontagne

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Worldships
« on: 02/11/2017 07:12 PM »
A Worldship, as defined in the fundamental papers of Bond(2) and Martin(1) in the JBIS, is a type of Starship that can move from star to star carrying an complet autonomous biome, and capable of operating indefinitely.

In this it differs from a colony ship(3), that requires a viable destination to colonize, and can probably be much smaller.

Although the power requirements for this type of vehicle probably puts it far into the future, if ever, can the study of Worldships serve a useful purpose today in providing a simplified setting that allows us to think about the Earth, our present Worldship, and to imagine the solutions that need to be applied to maintain its viability?

I have joined a few documents and images to start the discussion.  The illustrated worldship is 15km long and 5km in diameter.  It carries 10 000 people and is part of a flotilla of 4.

Hope some people find this interesting.

Most of the theoretical work and discussions that led to these designs was carried out over three Workshops done at the TVIW, Tennessee Valley Interstellar Workshop.

1- Martin, A. R. "World Ships-Concept, Cause, Cost, Construction and Colonisation." Journal of the British Interplanetary Society 37 (1984): 243.
2-Bond, Alan, and A. R. Martin. "World Ships-AN Assessment of the Engineering Feasibility." Journal of the British Interplanetary Society 37 (1984): 254.
3-WORLD SHIPS – ARCHITECTURES & FEASIBILITY REVISITED
JBIS, Vol. 65, pp.119-133, 2012
Andreas M. Hein, Mikhail Pak, Daniel Pütz, Christian Bühler and Philipp Reiss
« Last Edit: 02/11/2017 07:35 PM by lamontagne »

Offline colbourne

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Re: Worldships
« Reply #1 on: 02/13/2017 06:05 AM »
Maybe the way to use World Ships is to look for an object already going in the required direction and then building a colony on that.
There are many stars and objects which have been pushed into strange high speed paths, probably by collisions of galaxies.
As these will need to maintain life for  possibly thousands of years , looking for a star with planets that has been pushed on to a path maybe the way to go.

Offline Coastal Ron

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Re: Worldships
« Reply #2 on: 02/13/2017 06:39 AM »
It's certainly an interesting idea, and thinking about the requirements helps to identify (I hope) the path we need to take as we build our first rotating space stations.

I've been working on a design for a 1st generation rotating space station, so I've been giving a lot of thought to the various issues involved, but my assumption is that a 1st generation rotating space station would require a robust supply chain, which is not a surprise.  But I have been anticipating that there will be enough "land" available that some agriculture could be happen, which would decrease the amount of food supplies required.

As far as the Worldship goes though, based on the size you outlined it's going to require a lot of structural mass, which isn't a bad things considering the radiation shielding it would provide.  But that also means you would need to devote a lot of manufacturing resources to build such a fleet.

Even though they may be independent, and able to operate indefinitely, I would assume that taking in raw resources along their journey would still be a requirement since it would be impossible to not leak vital material along the journey, and some material may not be able to be recycled perfectly enough to keep from running out.  Which would require a fleet of service vehicles that would be needed for gathering the resources along the way.

Out of curiosity though, what would be the purpose of such vessels?  Why would the inhabitants, and their off-spring, want to spend all their lives traveling though space if it isn't to get to a destination?  Just curious what the thinking is...
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline MickQ

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Re: Worldships
« Reply #3 on: 02/13/2017 07:46 AM »
Those with the vision and drive to see humanity as a multi planet species would be the type of people that would set out on such a voyage knowing that they and generations of their offspring would never set foot on a planetary body.   The threat of a planet killer asteroid on a highly probable collision course would be another incentive.  Or, if you are like me and think that this world is rapidly going down the toilet.

Just waiting for RAMA to break into orbit.

Offline mikelepage

Re: Worldships
« Reply #4 on: 02/13/2017 09:17 AM »
It's certainly an interesting idea, and thinking about the requirements helps to identify (I hope) the path we need to take as we build our first rotating space stations.

I've been working on a design for a 1st generation rotating space station, so I've been giving a lot of thought to the various issues involved, but my assumption is that a 1st generation rotating space station would require a robust supply chain, which is not a surprise.  But I have been anticipating that there will be enough "land" available that some agriculture could be happen, which would decrease the amount of food supplies required.

As far as the Worldship goes though, based on the size you outlined it's going to require a lot of structural mass, which isn't a bad things considering the radiation shielding it would provide.  But that also means you would need to devote a lot of manufacturing resources to build such a fleet.

Even though they may be independent, and able to operate indefinitely, I would assume that taking in raw resources along their journey would still be a requirement since it would be impossible to not leak vital material along the journey, and some material may not be able to be recycled perfectly enough to keep from running out.  Which would require a fleet of service vehicles that would be needed for gathering the resources along the way.

Out of curiosity though, what would be the purpose of such vessels?  Why would the inhabitants, and their off-spring, want to spend all their lives traveling though space if it isn't to get to a destination?  Just curious what the thinking is...

Perhaps the journey is the reward?  ::)

But seriously, my thinking, ever since coming up with the spiral space station concept (video below), is that any kind of interstellar Worldship will never be "complete".  They will set off on their journey with whatever minimum viable population/agriculture is, and by harvesting materials along the way, the ship size would grow as the colony does.

I actually tend to think that any Worldship that was truly successful might reach the "destination" star and have cause to wonder what was so great about planetary surfaces, anyway?  Go down a deep gravity well, only to deal with all this uncontrolled weather and seismic activity.  Why would you bother?  ::)


Offline Rei

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Re: Worldships
« Reply #5 on: 02/13/2017 10:34 AM »
That diagram is far too simplified. 

1) Enclosed biomes with plants trend toward instability, not stability - see Biosphere 2 as an example.  You need to be able to make everything that either humans, plants, or both need, in order to be able to account for deficiencies on one end, because sooner or later, they will arise.

2) Every process has consumables.  Every device has parts that can break or wear out.  You need to be able to make them.  Chemical production dependency chains can be long.  Just to pick a random example: look up Vectran, a popular fabric for space applications.  Start tracing back its dependencies all the way back to basic Sabatier synthesis.  Or worse, PBO (Zylon - popular for high temperature applications), or even worse, its amorphous relative PIBO.

Don't get me wrong, humanity will get there eventually.  Learning how to do this is a fundamental part of colonizing planets, meaning that colonization will inherently eventually lead to such "Worldships".  But it's no short road, and that diagram gives a misleading impression.
« Last Edit: 02/13/2017 10:35 AM by Rei »

Offline TakeOff

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Re: Worldships
« Reply #6 on: 02/13/2017 10:49 AM »
Out of curiosity though, what would be the purpose of such vessels?  Why would the inhabitants, and their off-spring, want to spend all their lives traveling though space if it isn't to get to a destination?  Just curious what the thinking is...
Because a free floating "world", purposely created for our best, could be made so very much more pleasant and productive than the Earth we happened to inherit from thoughtless rocks and plants. The question is rather why it would be interested in traveling to another planetary system, since life in the world ship is so much better than it could be on any planet, it might prefer orbiting and absorbing some high energy phenomena. Unless "other civilizations" are discovered and we follow our instinct to hunt or mate with anything that moves.


Quote
Out of curiosity though, what would be the purpose of such vessels?  Why would the inhabitants, and their off-spring, want to spend all their lives traveling though space if it isn't to get to a destination?  Just curious what the thinking is...
Eternal life! Human life time is increasing by X months every year now, and it is a long and accelerating trend. Biological engineering might be the thing that cracks the obstacle to human interstellar flight. If you live for ever you might not care much about spending a mere ten thousand years on the road in order to be honored as a great explorer or just to have a nice holiday.


Dying is getting old! I think we need to go beyond death in order to make interstellar progress, and it looks as if it is actually happening. Some social changes will come with eternal human individuals, but at least evolution we might replace by purposeful bio engineering. I'm just lamenting being one of the few last mortal generations of humans, after a string of tens of thousands. Like having a Lotto ticket identical to the eternally winning number, except for the last digit.
« Last Edit: 02/13/2017 11:02 AM by TakeOff »

Offline lamontagne

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Re: Worldships
« Reply #7 on: 02/13/2017 12:35 PM »
That diagram is far too simplified. 

1) Enclosed biomes with plants trend toward instability, not stability - see Biosphere 2 as an example.  You need to be able to make everything that either humans, plants, or both need, in order to be able to account for deficiencies on one end, because sooner or later, they will arise.

2) Every process has consumables.  Every device has parts that can break or wear out.  You need to be able to make them.  Chemical production dependency chains can be long.  Just to pick a random example: look up Vectran, a popular fabric for space applications.  Start tracing back its dependencies all the way back to basic Sabatier synthesis.  Or worse, PBO (Zylon - popular for high temperature applications), or even worse, its amorphous relative PIBO.

Don't get me wrong, humanity will get there eventually.  Learning how to do this is a fundamental part of colonizing planets, meaning that colonization will inherently eventually lead to such "Worldships".  But it's no short road, and that diagram gives a misleading impression.

Any suggestion what could be added, while retaining readability?
I draw your attention two three grey boxes: Stores, recycling and industry, that I hope address some of criticism.  I guess I should add an arrow to supplement the stores from time to time, since the worldship is an open system, operating in an environment where asteroids and comets are likely to be the primary ressources, plus the fuel to drive the magic fusion drive.
I drew the diagram to better understand the water cycle, and I have covered, I think, the main elements.  But my ignorance knows no limits and I would love to improve the diagram.


Offline lamontagne

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Re: Worldships
« Reply #8 on: 02/13/2017 12:38 PM »
Maybe the way to use World Ships is to look for an object already going in the required direction and then building a colony on that.
There are many stars and objects which have been pushed into strange high speed paths, probably by collisions of galaxies.
As these will need to maintain life for  possibly thousands of years , looking for a star with planets that has been pushed on to a path maybe the way to go.
Another interesting possibility is to move from rogue planet to rogue planet.  The appear to be a number of these, with an average distance that might be as small as a light year apart.
If  the worldship can last, then colonies are perhaps not the best offspring for them.  Perhaps worlships build other worlships.

Offline lamontagne

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Re: Worldships
« Reply #9 on: 02/13/2017 12:43 PM »
Those with the vision and drive to see humanity as a multi planet species would be the type of people that would set out on such a voyage knowing that they and generations of their offspring would never set foot on a planetary body.   The threat of a planet killer asteroid on a highly probable collision course would be another incentive.  Or, if you are like me and think that this world is rapidly going down the toilet.

Just waiting for RAMA to break into orbit.
The children will not be highly motivated, though.  I's always a problem with visionary social projects.  The worlships need to find their justification in themselves, I believe.
I think these type of vehicles may be a natural consequence of the expansion of life, and may, if better technologies are not developed,  serve as a vector to move life beyond multiplanetary to interstellar.  But they are perhaps not the most likely way.  Don't really know, but am interested in opinions on this.

Offline lamontagne

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Re: Worldships
« Reply #10 on: 02/13/2017 12:47 PM »


I actually tend to think that any Worldship that was truly successful might reach the "destination" star and have cause to wonder what was so great about planetary surfaces, anyway?  Go down a deep gravity well, only to deal with all this uncontrolled weather and seismic activity.  Why would you bother?  ::)


There would probably be some people interested.  Planets are big and will probably appeal to some.
But it's unlikely, IMHO, that the worldship would be abandoned as a mere transportation device. 
I think an interesting coloray of the size of worldships is that the same technology can be used to make much smaller and faster ships (unless the drive, like our sun, has a minimal size)  so a worldship should never be the first somewhere...  and would probably be wise to send out scouts.


Offline JasonAW3

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Re: Worldships
« Reply #11 on: 02/13/2017 02:06 PM »
      As has already been stated, replenishment of consumables of all types, is a necessity for the Worldship concept to work.

      While some have suggested stopping to utilize various comets and asteroids, it occurs to me that an alternative, which also resolves an energy issue, as well as thrust, does exist, in theory.

      The Bussard Ramjet.

      This system has several advantages to most conceptual resource gathering systems for interstellar craft.

      1)  The electromagnetic ramscoop would not only gather free hydrogen from the interstellar medium, but also small debris, such as dust and micrometeroids, which could be harvested prior to going into the fusion constriction section of such a system.

      2)   Such a system would likely have an issue with carbon "coking" as hydrogen becomes fused into various heavier elements, up through carbon.  (Should the system ever fuse to iron, then the reaction would stop, and the decoking teams would be in a good deal of trouble as they haven't been doing their jobs!)  Obviously, the fusion torch would be periodically shutdown to remove and harvest the coke, as it would contain numerous useful elements that would likewise be created as fusion byproducts.

      3)   The Electromagnetic scoop would also act as a debris shield, preventing or reducing potential damage and frontal erosion for crafts moving at a significant fraction of the velocity of light.  Most debris encountered by these Worldships, will likely be of atomic or microscopic scales.  Such a system should be able to divert the majority of this debris, up to large pebbles, with the ramscoop.  Larger debris would require either a ceramic ablative shield, for intermediate sized impacts and erosion, or a slight object impact avoidance maneuver.  (Objects of dwarf planetary scale or larger would, of course, require a significantly larger OIAM).

      Overall, it seems the smaller the habitat, the more frequently resupply will be required.  This assumes a resource reserve proportional to the size of the habitat and population.  Planets in orbit around stars have a significant advantage as they would have a larger resource to population ratio compared to the hypothetical Worldships,

a)  They have a constant energy source, that requires no maintenance or refueling. (At least for several billion years)

b)  They have electromagnetic fields and atmospheric depth sufficient to mitigate most radiation damage.

c)  They also achieve a certain level of passive resupply from micrometeors, meteors and comets, falling into the atmosphere,

d)  They have a fairly stable biological recycling system already established, again, requiring little maintenance.

     Overall, Worldships will never be as efficient as actual planetary environments, but they can be made much more so with a sufficiently large and complex biosphere, and a high enough initial store of raw resources.
My God!  It's full of universes!

Offline Rei

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Re: Worldships
« Reply #12 on: 02/13/2017 02:08 PM »
Any suggestion what could be added, while retaining readability?
I draw your attention two three grey boxes: Stores, recycling and industry, that I hope address some of criticism.

That's like adding a box that says "technology".  It means nothing.

Quote
I guess I should add an arrow to supplement the stores from time to time, since the worldship is an open system, operating in an environment where asteroids and comets are likely to be the primary ressources

Huh?  I thought your point was ships that would be traveling between stars - a process that can take hundreds or even thousands of years for relatively short hops.  No stopping en route when you're doing semi-relativistic travel, if you can even find anything en route to stop at. 

Offline guckyfan

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Re: Worldships
« Reply #13 on: 02/13/2017 03:16 PM »
I don't see worldships travelling at semi relativistic speeds. 1 or 2% of light speed is fully enough to go 10 or 20 light years.

I also don't see a need for replenishing on the way. Also no need for planets in the target system. Every sun should have at least an Oort Cloud with plenty of material to stock up and build new worldships before continuing the journey.

Offline lamontagne

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Re: Worldships
« Reply #14 on: 02/13/2017 03:54 PM »
Any suggestion what could be added, while retaining readability?
I draw your attention two three grey boxes: Stores, recycling and industry, that I hope address some of criticism.

That's like adding a box that says "technology".  It means nothing.

Quote
I guess I should add an arrow to supplement the stores from time to time, since the worldship is an open system, operating in an environment where asteroids and comets are likely to be the primary ressources

Huh?  I thought your point was ships that would be traveling between stars - a process that can take hundreds or even thousands of years for relatively short hops.  No stopping en route when you're doing semi-relativistic travel, if you can even find anything en route to stop at.
The ship stocks up every few hundred years, when it reaches stellar system.  It doesn't travel faster than 1% of the speed of light, and most of the time much more slowly.  I expect it to be continuous boost, because that has the lowest power requirements.  For the entire trip, it will encounter at most a few tonnes of dust, so I'm not counting on that.

It's a simplified graphic, do you expect me to illustrated the entirety of technical civilisation in a single diagram?  The main thing I want to show is the energy scales involved, in particular the tremendous power of even the most minimal drive system, the all importance of light in an ecosystem and the fact that it cannot exist without continuous intervention, that it is in fact an unstable and open system.  the vehicle itself is an unstable system; long rotating cylinders are inherently unstable. 

The ship ecosystem is much too small to be stable, but I expect it to have a certain inertia, than can help in its regulation.  There are no non technological mechanisms that I know of to replicate many of the larger scale parts of the Earth.  Lighting and geological processes for CO2 renewal come to mind.

I would be happy to improve the graphic.  I don't quite understand what you think is missing.

Offline lamontagne

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Re: Worldships
« Reply #15 on: 02/13/2017 04:09 PM »
Despite its large size, the Worldship should be hit during the trip by a maximum of 1.3 tonnes of gas and 5 kg of dust, leading to the evaporation of approximately 1mm or less of shielding material(1).

The period inside a solar system would be much more risky.  The ship would be hit regularly by micrometeorites and would need to be repaired from time to time.

I don't really care about the drive.  If it is fusion, I would like it to be deuterium-deuterium, as this is relatively abundant and easier to do than deuterium tritium.  I just want to point out that it will create much more power than the ecosystem requires, over 10 000 times more power.  The people on the ship will have abundant energy resources.  Very, very abundant.  And will likely come from a civilisation that has the same energy abundance. 

1) Project Icarus: A Review of Local Interstellar Medium Properties of Relevance for Space Missions to the Nearest Stars
(Published in Acta Astronautica, 68, 691-699, 2011)Ian A. Crawford

Online gospacex

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Re: Worldships
« Reply #16 on: 02/13/2017 04:10 PM »
      As has already been stated, replenishment of consumables of all types, is a necessity for the Worldship concept to work.

No, it is not a necessity. Earth does not need to replenish anything for 4.5 billion years already. All it needs is solar energy.

Worldship is, by definition, a ship large enough to have fully closed cycles for all materials, except energy sources (probably fission or fusion fuel).

Quote
      While some have suggested stopping to utilize various comets and asteroids

Some did not do the math to see how expensive it is to decelerate to be able to catch any such comet.

Quote
it occurs to me that an alternative, which also resolves an energy issue, as well as thrust, does exist, in theory.

      The Bussard Ramjet.

IIRC nobody yet posited a plausible method how exactly Bussard ramjet is supposed to fuse hydrogen. Protium fusion is HARD.

Offline lamontagne

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Re: Worldships
« Reply #17 on: 02/13/2017 04:18 PM »
A Worldship is going to be a lot more leaky than Earth, so new resources are probably required much faster.
I also think it is likely a worldship will be a system that needs to grow, and in a sense, reproduce, and that also requires resources.  I would expect one world ship to come in to a system, and a number of worldships to leave.
woldships are big on a technological scale, but tiny on a cosmic scale.

Although a bussard ramjet is a neat idea, it is not required for a worldship.  It adds another layer of complexity to what is already a (understatement coming here :-) complex system.


Online gospacex

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Re: Worldships
« Reply #18 on: 02/13/2017 04:21 PM »
A Worldship is going to be a lot more leaky than Earth, so new resources are probably required much faster.

Indeed. Every few hundreds of years, it will need to stop in a suitable Oort Cloud :D

Offline cro-magnon gramps

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Re: Worldships
« Reply #19 on: 02/13/2017 04:58 PM »
A Worldship is going to be a lot more leaky than Earth, so new resources are probably required much faster.

Indeed. Every few hundreds of years, it will need to stop in a suitable Oort Cloud :D

why stop "in" the Oort Cloud
with thousands of years between stops
the technology they start with will not
necessarily be the ones they have even
with the first stop...

Cities in Flight, by James Blish might be a good primer to read...
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