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bussard ramjets, cryonic stasis, and exoplanetary colonization

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bussard ramjets, cryonic stasis, and exoplanetary colonization

what will it take?

from GalCiv2 Forums
hello everyone,

i'm a bit of a writer, and i can't help but feel drawn to science fiction. that shouldn't be surprising.

lately i've been reading up a great deal on theoretical physics, exobiological speculation, and all that. i was dismayed at first to learn that the chances of faster-than-light travel being physically possible are slim. it was also pretty discouraging when i sat down and looked at the actual speeds that'd be required to traverse sizable parts of the galaxy in a single conscious lifetime. it was a kick when i was down to learn about how difficult terraforming probably would be. but the more i've been learning, the more i've been excited about telling a different kind of science fiction story.

to draw an analogue to our world, the thing that made both the european colonial age and the modern process of globalization have been technology. it's not that we couldn't go to various places around the world before, it just cost too damn much to make anything worth it. i got my BA in sociology, and these sorts of things interest me.

if FTL travel isn't possible, then more than likely it'll be too damn costly to ever colonize beyond our own solar system as the way it's been envisioned in most of the celebrated scifi universes. But there are examples such as Arthur C. Clarke's Songs of a Distant Earth or Sid Meier's Alpha Centauri where humans colonize to escape destruction on earth.

recently i had the chance to meet both Kim Stanley Robinson and Geoff Ryman. Robinson is a hard scifi writer after my own heart; the Mars Trilogy is a really interesting look at our first attempts to colonize within our own star system. Ryman was actually more interesting to talk to, though. maybe because few people have ever heard of him (i was only there because i work at UCSD where he was being hosted). but i actually got to talk to him. he said he thinks we probably won't ever leave our galactic neighborhood.

i'm interested in writing a hard scifi story (or series) myself. i'm interested from a sociological point of view: what would drive us to colonize space? from a writer's point of view, i want to keep the earth around, so i'm not interested in a flight from disaster. what would societies be like after colonies were established? trade would be difficult, but not impossible. same goes for war.

while i'm certainly interested in contributions along those lines, i'm also interested in learning more about the hard science and engineering behind interstellar travel. i've got a lot of questions i haven't been able to answer through wikipedia and google alone. but i'm not about to list them all here.

it seems like a discussion about real ("real") colonization and space travel could use a place on these boards.

i'll kick it off. i've been reading up on propultion especially, and bussard ramjets seem like the most economically feasible option since they gather their fuel as they go - perhaps especially if it could be hybridized with another form such as antimatter-catalyzed fusion. the wikipedia article on bussard ramjets describe that they'd probably need what is essentially a magnetic funnel or ramscoop to gather interstellar hydrogen as propellant.

The mass of the ion ram scoop must be minimized on an interstellar ramjet. The size of the scoop is large enough that the scoop cannot be solid. This is best accomplished by using an electromagnetic field, or alternatively using an electrostatic field to build the ion ram scoop. Such an ion scoop will use electromagnetic funnels, or electrostatic fields to collect ionized hydrogen gas from space for use as propellant by ramjet propulsion systems (since much of the hydrogen is not ionized, some versions of a scoop propose ionizing the hydrogen, perhaps with a laser, ahead of the ship.) An electric field can electrostatically attract the positive ions, and thus draw them inside a ramjet engine. The electromagnetic funnel would bend the ions into helical spirals around the magnetic field lines to scoop up the ions via the starship's motion through space. Ionized particles moving in spirals produce an energy loss, and hence drag; the scoop must be designed to both minimize the circular motion of the particles and simultaneously maximize the collection. Likewise, if the hydrogen is heated during collection, thermal radiation will represent an energy loss, and hence also drag; so an effective scoop must collect and compress the hydrogen without significant heating.


talk about kick-butt imagery! spirals of heated gas careening towards a ship only to be fused and expelled in a jet plume? sweet.

anyway, i've written enough, and i hope it hasn't put anyone off. some of the the community here has proven to be very well read with regard to these kinds of science, so i thought it'd make a great topic for discussion: all things related to space exploration and colonization with reasonable extrapolations of current technology.

my biggest point of curiostiy was with respect to ramjets, so i'll take the kickoff: could the spiral motion of the inbound gas somehow be harnessed to artficially generate gravity by rotating the ship, instead of producing drag?

any volunteers?

final words: i hope no one minds my double-motive. i won't try to steer any dicussion, though if things quiet down i might pose more general questions to keep it going; i encourage anyone interested to pose your own!
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Reply #176 from GalCiv2 Forums Top
where as the hd needs power and the book needs light.
Reply #177 from GalCiv2 Forums Top
I think the term you're looking for is "Mercantilism"


Thanks, I knew that didn't sound right   

I would think that the initial colony wouldn't require that much construction.


There is also the option of biofuels; we could use processes that we have to create oil or ethanol with vegetation, whether this means setting up a distillation apparatus, or maybe for something slightly more sci fi


all or most buildings would be one story.



Again, I think we are underestimating construction needs here. Even a for a small colony of 1000 people, we are gonna need large industrial and storage complexes. Refineries and plants could easily top 3-4 stories, In addition you'll need systems like Water towers (5-6+). Waste treament plants are also large. For agriculture, grain storage, also a multi story silo(s) is needed. Most builds would be multi story. Its more efficient. Hundreds of little building scattered around requires more infastructure (pipping, power, water, heating, roads, etc). Than fewer larger buildings. Its all about space. You need to make the most out of the space provided in the colony ship.

Hdd drives for books and info makes the best sense, It its pretty obvious that the colony will need a central computer system (Colony LAN) from the start. The computers would hold the blueprints for the colony, and the programs/specifications for some of the facilities functions. Automation will be a big key as unlike here in earth, manpower will be a scarce resource. Since a ship the size of the colony ship could never "land", The computers could probably stay in the ship and simply transmit to the colony. The ship would be like a modern wireless router, handling communication within the colony while sending and recieving info from earth.
Offworld Trading Company
Reply #178 from GalCiv2 Forums Top
Hdd drives for books and info makes the best sense, It its pretty obvious that the colony will need a central computer system (Colony LAN) from the start. The computers would hold the blueprints for the colony, and the programs/specifications for some of the facilities functions. Automation will be a big key as unlike here in earth, manpower will be a scarce resource. Since a ship the size of the colony ship could never "land", The computers could probably stay in the ship and simply transmit to the colony. The ship would be like a modern wireless router, handling communication within the colony while sending and recieving info from earth


A central computer reminds me of I robot! That movie is awesome!
don't you hate it when super computers go bad?  !  !  
Reply #179 from GalCiv2 Forums Top
Again, I think we are underestimating construction needs here. Even a for a small colony of 1000 people,




i can't see any ship being bigger than 100 people.

and if we go by the space games the colony ships will land and become the starter for the colony/colonies.

thus your power, waste processing, housing and other needs except fuel is already met.
Reply #180 from GalCiv2 Forums Top
Even a for a small colony of 1000 people, we are gonna need large industrial and storage complexes.


I think that you are overestimating the quality of life people need. A feasible colony is going to have to cut every corner they can, and quite simply, a colony of 1000 just isn't going to have this much equipment. Much of this depends on the conditions of the planet, but assuming roughly Earth-like conditions, tents would serve for housing and storage of equipment. Beyond this, I'm thinking that much of their initial construction would probably be primitive, buildings of stone, mud, or possibly wood around a simple metal frame that they already had. Things like water towers aren't necessary either, if there is no plumbing. Heating and roads would be no more than fires and dirt paths. The only complex equipment we need initially is a communications up-link to the mother ship and the appropriate computers for this, which could be housed in a tent, food storage/refrigerator, also housed in a tent, various vehicles and power generators, which would likely have been prefabricated to use whatever resources they had already detected. Wind, water, and solar power are particularly attractive because you simply erect the generator and they begin to function. But technologically the colonists would basically start over again; they would just have a better understanding of what comes next.

Now, if there were several hundred thousand people, or perhaps millions, then they could start with a full factory/support structures, but all available equipment would be reserved for this; people's homes would still be primitive like I said above. It would take several decades, even centuries, to establish anything modern, let alone anything like Earth's standards in this future.

So you're right, a lot of construction is required to build all these factories. Feasibly, though, the answer isn't to bring all the necessary equipment over; the answer is that they just wouldn't construct all this stuff at all, they would have to get started without the tools of modern life.
Reply #181 from GalCiv2 Forums Top
I haven't read all of this, but I'll put my 2 cents in. I heard, recently, that Russia is trying to get to the moon in 2025 and put a moonbase on it by 2027.
Reply #182 from GalCiv2 Forums Top
again the colony ship in my opionion.

will be built to start with 100 or so people. will be built in space and designed for one landing on it's butt. thus you will have your starting power plant water treatment and houseing. remember after the ship lands all the power it would use to move can now be used to power lights. this also means that all of the rooms/buildings in the ship will need to be designed to pivot. either manually or auto.
Reply #183 from GalCiv2 Forums Top
whew busy weekend guys, sorry i've been incommunicato. let's see i've read through everything i've missed, but in the interests of remaining coherant and breif, i'll just state my opinion.

i think cost will dictate how colonization takes place at any particular time, but i don't see one method being obivously better than any other. and looking at this from as a writer, i don't want any single method to be central. i'm thinking about framing this series as if it narrator were looking back on millions of years of human history: even though individual stories will probably be linear and such, the series as a whole will be much less so.

i don't think we'd want a single small (relatively speaking) ship to found a colony on its own because of the genetic bottleneck it'd create. human gametes can be frozen as a way around this. it'd be an interesting plot turn if, during one of the first colonizations, the ship had a have a restricted crew, so to optimize reproduction only women were sent? that'd be an interesting twist for the foundation of a new colony and culture.

but one of the reasons i can imagine to push colonization is to free up population restrictions in Sol, so large, city-sized ships carrying anywhere from tens of thousands to millions of colonists. these things would be more like mobile space stations, and in that sense they could function like Von Neumann ships, slowly seeding colonies throughout the galaxy. most of the colonists would be kept in suspended animation for the duration of the trip and even a great deal of time after arrival. keep in mind, people themselves don't take up that much space. the entire population of the earth could fit standing shoulder-to-shoulder in an area the size of Rhode Island.

during transit to a new star (phase 1), only required facilities would be operational. a number of peripherial facilities would be 'collapsed' - these would be the infrastructure needed to support the a larger crew. this crew would awaken shortly after arrival. they'd immediately work to 'expand' the ship's dormant facilities - housing, waste processing, food production - so that they can survive on the station. after they've secured the facilities for themselves and mission leadership - the phase 2 crew - who's primary objective is to quickly construct the further facilities that'd be needed to support the entire dormant crew - other space stations, a space fountain, planetary bases - the works. batches of colonists would be slowly awakened from SA as the colony was built up in the new system.

after the colony had become prosperous and the population large enough, the original colony ship would be returned its transit stage, a new crew would be put into SA, and the ship would be on its merry way.

i think this has the advantage of low initial investment (only 1 ship) and also a level of security a small ship can't offer. if the crew finds something unexpected upon arrival to their destination, and it'd be a total detriment to founding a new colony, they can just pick a new star and head to it.

i know at this point the cost seems unimaginable, but give it a few thousand years and i think we could have the infrastructure to build something like that in Sol.
Reply #184 from GalCiv2 Forums Top
we have the infrastructure right now to build the smaller ship i was talking about. of course it would be a gen. ship if going between stars.
Reply #185 from GalCiv2 Forums Top
we have the infrastructure right now to build the smaller ship i was talking about. of course it would be a gen. ship if going between stars.


what i meant about infrastructure had less to do with ability and more to do with cost. we have the infrastructure now to build a mega city-ship too, but with our current level of infrastructure it'd be insanely expensive to build either one right now.

true, it'll be 'affordable' (relatively speaking) to build the kind of small ship you describe a lot sooner than the kind of mega-ship i described. but i don't think any major power is going to have much reason to build one - i could see an rich eclectic type funding it, and i could also see trips for scientific exploration (but not colonization).

i don't see generation ships at all. we already have major breakthroughs on how to induce effective states of suspended animation, and we're rapidly producing research that could eventually lead to out ability to indefinately prolong or even stop senescence (biological aging). the major reasons i see for building a small ship instead of a big one are reducing cost and reducing fuel/energy needs, and both ends are better served if most of the crew are in suspended animation for the duration of the voyage.
Reply #186 from GalCiv2 Forums Top
Von Neumann ships


I don't know the basis behind these ships, but the idea sounds really good. The problem with our earlier colony setups was that we treated the ship more like a gel capsule; delivering the colony to the planet. Resources are a huge problem. We couldn't start out with a very advanced colony, but if we made it too simple, its survival could easily be wiped out by something trivial.

However, if the colony ship, built the colony, sent it down, and supported it, like the Von Neumann ship, I think a colony would have a greater chance of surviving. Instead of being on the planet with everything you have, the colony couuld rely on the ship for support and the ship, already being built, equiped and established, could do things that the colony might not be able to do in its inital developement. In addition, the ship would be safe from adverse events/conditions on the planet. Everything from machining to power, to food, to people could be provided by the ship. That would solve almost all of our logistics/survival issues.

You would just have to assume that the ship is self-sufficient or has a great deal of resources in its hold and the ability to collect and process resources on the go - which isn't too far fetched.
Reply #187 from GalCiv2 Forums Top
Von Neumann ships



think of von neumann ships as independence day. only after they build a new mother ship they leave. if you don't destroy them.
Reply #188 from GalCiv2 Forums Top
Von Neumann


was perhaps not the best word. such ships were originally called Von Neumann probes, since the guy who thought them up didn't imagine them to be ships per se. i think to some extent, his name can be applied to any self-replicating space craft.

my idea itself isn't exactly self-replicating in a direct sense, either. after a ship establishes a colony and leaves, the new colony could certainly build a copy of it if they faced pressures that'd make it an attractive project: and in that sense, it is sort of self-replicating.

also, i apologize for the horrible, horrible composition of my earlier post (about the ships in question). i re-read that, and all i can say is that it inspired me to re-check the work i'd done this morning.
Reply #189 from GalCiv2 Forums Top
its all good. I think the concept has a pretty good ground to stand on, so to speak.
One ship traveling around "droping down" colonies certianly makes sense. The technology and resources are already there when a new colony is founded (courtesy of the ship), so it will establish much faster and will be able to repair, replensih, and even enhance the colony ship (YaY - A mother ship!!). The colony ship could then depart and start all over again.

It certianly seems more efficient than sending Colony ships that are "used up" in the colony's creation. While a Von Neumann ship would certianly have a higher cost, it seems to have a much higher chance of sucess and potential.
Reply #190 from GalCiv2 Forums Top
i can't see any ship being bigger than 100 people.


Actually, after you get out to space the weight and size of the cargo no-longer matters becuase there is no gravity to create tension and stress on the ships hull.
Reply #191 from GalCiv2 Forums Top
Actually, after you get out to space the weight and size of the cargo no-longer matters becuase there is no gravity to create tension and stress on the ships hull.



true

but you need so many acres of land to feed one person for a year i think that is 5 acres of land. don't know what that translate to hydroponics.


plus each person needs so much water which can be a closed system. each person needs so much air which could also be a closed system. but you have to get those closed systems started.
Reply #192 from GalCiv2 Forums Top
Just for construction purposes, its more feasible to have a fleet of ships rather than one huge ship. Or at least you would build several ships that could dock together, forming a composite ship from the modules.
Reply #193 from GalCiv2 Forums Top
Hi!
Actually, after you get out to space the weight and size of the cargo no-longer matters becuase there is no gravity to create tension and stress on the ships hull.


true

I'm sorry but that's wrong. When you change the speed (and ship will do that), tension and stress on the ship's hull comes back. Mass does not go away with the gravity.

BR, Iztok
Reply #194 from GalCiv2 Forums Top
but you need so many acres of land to feed one person for a year i think that is 5 acres of land. don't know what that translate to hydroponics.


I believe the Hunger Project at one point demonstrated a pre-fab geodesic dome semi-hydroponic greenhouse design that would feed a family of 4, 'for a year', i.e. indefinitely. I think it was ~40 feet across and 15-20 feet high.

I know for a fact that if he had strictly worked his gardening full-time, and had a year round controlled environment, my dad could have fed a family of 4 from the 3/4 acres he kept under intensive gardening every year.

drrider
Reply #195 from GalCiv2 Forums Top
I know for a fact that if he had strictly worked his gardening full-time, and had a year round controlled environment, my dad could have fed a family of 4 from the 3/4 acres he kept under intensive gardening every year.




sorry i should have said depending on quality and length of growing season.
Reply #196 from GalCiv2 Forums Top
whew that got things rolling again! let's see...

hi Iztok, drrider and JubJub - welcome! i'm glad our discussion is snagging a few more people.

Actually, after you get out to space the weight and size of the cargo no-longer matters becuase there is no gravity to create tension and stress on the ships hull.
true
I'm sorry but that's wrong. When you change the speed (and ship will do that), tension and stress on the ship's hull comes back. Mass does not go away with the gravity.

BR, Iztok


exactly what i was going to say, but i think it's also connected to millertime's statement:

Just for construction purposes, its more feasible to have a fleet of ships rather than one huge ship. Or at least you would build several ships that could dock together, forming a composite ship from the modules.


hmm i'd say it depends on a few factors. smaller ships would indeed be easier to construct, damage to one would't endanger a fleet, and they'd be less subject to the inertial stresses caused by travelling at relativistic speeds.

on the other hand, a very large ship could house facilities smaller ships might not be able to. different modes of trust might also have different advantages at different scales.

i think the enormous hybrid ramjets i described earlier would work better on larger scales - at least parts of it. when we talked about them, we did some basic calculations that highlighted the fact that the magnetic ramscoop would have to be huge. someone pointed out the kinds of problems a single field generator would present. my way around this is to imagine a few massive rings projected in front of the ship and create overlapping magnetic fields - each weak enough in overall strength to avoid crushing the hull and nasty side effects, but large enough in total to scoop up a pretty decent amount of intersteller hydrogen.

a traditional ramjet works by compressing a large amount of gas, but i suggested that to generate a greater overall thrust, the compressed hydrogen could also be fused. the mechanism i described would require a particle accelerator to generate the antimatter needed to initialize the fusion reactions - another piece of pretty sizable technology.

i think there are a few construction techniques that could be applied to facilitate the kind og structural sturdiness a huge ship would need. for starters, it doesn't need to be perfectly rigid: the same concept is applied to sky scrapers. a large enough structure might move more like an enourmous jelly fish.

the second point harkens back to my mention of space fountains, the alternative to space elevators to avoid the need for expoentially stronger materials than we have now.

the bottom line with those is power: a ship like this would need a lot of it. solar would help, but i don't think it'd cut it by any means. i think the greatest technological gaps required to build a ship like this would be in generating power. fusion has much potential and seems the most realistically attainable; however i think the real challenge will be with efficiency.

i don't just mean specifically with generating power, either. i also refer to reclaiming it. there are a few methods i've read that could be used to improve this. all of our current power-generating methods rely on hydro-thermal energy conversion AFAIK: turning heat into mechanical force and that into electrical energy.

danielost's post about solar paint, and the research i did on it, led me to think that with enough development we might get much better efficiency by directly converting heat to electricity; this would require two things: the ability to contain a fusion reaction such that its only primary energy release is by EM radiation, and the development of photovoltaic technology with extreme efficiency, especially for IR frequencies. this same method could allow energy to be extracted directly from the drive without generating drag (though i think dedicated fusion generators would also be needed to maintain the total power needs).
Reply #197 from GalCiv2 Forums Top
maybe a fleet of population ships and one larger one for manufacturing modules. ie a smelter.

the larger ship only requiring a crew for the flight. and during flight training on how to operate the equipment.
Reply #198 from GalCiv2 Forums Top
smelter


This just brought an industrial quandry to mind. Many of our industrial process, like metal purification, smelting, etc rely heavily on gravity. Even the thermal-hydro-electric system takes gravity into account with its engineering. It's known that our plants also can sense gravity to grow in teh right direction. Obviously we could remedy this by having parts or the entire ship rotate, but, If I remember my physics right, wouldn't that generate a force in the direction of tavel of the ship (perpendicular to the spin, right?)? Ie, everytime the ship turns, it would have to fight against its own rotation or the rotation would slow down. Especially if significant portions (in terms of mass) are rotating?

Just a little devil's advocate but, Would a fleet be better? I mean you would have tons of redundancy in terms of equipment for each ship. In addition, the constant travel, docking between the fleet as its travels, not to mention that each ship would have to recalculate its trjectory and mass everytime it sends out a shuttle, supplies, docks, what ever. I was kinda assuming that our giant ship would be built in sections.

Just being a devil's advocate. I'm really enjoying the discussion.

Hey. Perhaps a large "Mother ship" with a small fleet of more specialized support ships. I mean a huge ship wouldn't bea ble to carry out a mining operation safely. But smaller ships could harvest materials and return home? The large ship would have the least mobile comppnenets, People, hydroponics, industry, supplies. Smaller ships could carry fuel, defence, mining, scouting, etc? Would that work?
Reply #199 from GalCiv2 Forums Top
If I remember my physics right, wouldn't that generate a force in the direction of tavel of the ship (perpendicular to the spin, right?)


I think you're thinking of electromagnetic forces, where a spinning magnet or a solenoid generates an orthogonal EM force.

Would a fleet be better?


What I envision is a staggered fleet, where individual ships (we'll just say medium-sized, despite our lack of a frame of reference) are sent one by one, say 6 months between each or so. The first one would only carry a skeleton crew, or maybe be fully automated, and upon arrival would begin construction. The following ships would bring colonists who would be required at different stages of development, starting with engineers and architects for construction, then farmers or whoever knew modern food producing techniques, then probably doctors and scientists, etc. Eventually they would just send anybody, because the colony would be well established.

The reasons for trying to keep ships from getting too big is A/ the stress placed on the ship by high-speed travel, and B/ simply where are you going to build it?

One option would be if we knew we could begin producing fuel from the colony at an early stage is that we could send the colony ships back to Earth on autopilot. This would reduce the building required. We would still probably need around 20-30 ships if we were going to have ships depart every year or so.

We would need smaller ships to be used in specialized operations, but I really don't consider these as "ships" because they would be localized around the mother ship, ie they wouldn't be capable of interstellar travel; they are part of the mother ship's equipment.
Reply #200 from GalCiv2 Forums Top
if the first two or three ships land you wouldn't need archtects at first.