dystopic dystopic

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 #451 from GalCiv2 Forums Top
When I was thinking of jettisoning tanks/engines I was thinking in terms of continual thrust while jetisoning (pretty much just like the space shuttle). Why thrust dead weight as we start a sling shot?


As soon as the engines jettison, they stop imparting thrust to the main body, so there's no way to have thrust without the weight of the engines.

a swinging arm space station!


I think I mentioned rotating space stations earlier in the thread. But, anyways, we actually already have plans (though I don't think they are being implemented yet) for a station that consists of little more than a spinning rod with some sort of claw mechanism at one end and a counter-weight at the other. It is designed as an alternative to current delivery systems for lunar and martian landers, so that we only use little more than a shell with the rover inside rather than wasting resources on a full, complex ship.
Reply #452 from GalCiv2 Forums Top
voyager 1 used sling shots to get it where it is. you cannot speed up without an energy source this would be gravity. you also cannot change direction without an energy exchange.


i get what you mean now. i don't think anyone has said gravity assists don't increase the velocity of a travelling object (though in hindsight i may have given that impression when was talking about leaving a stationary orbit). they end up with more momentum (accounting for what's lost to gravity itself) than their fuel could provide, however the energy doesn't come from gravity; the energy comes from the planet's own momentum. when you swing a ball on a rope and let go, it's energy doesn't come from the rope, but from your swinging movement.

also, i like your "grandma" explanation, but i still don't understand what you mean by "tail lander" (the lander part is clear enough, but what do you mean by appending 'tail' into the phrase?).

also, i don't really agree with the grandma premise. for starters, in the future we might be able to prevent natural aging all together. but beyond that, space flight needn't ever become "truly" available by that standard ("until grandma can do it") to still be commonplace. incentives will be economic, and generally the elderly are no longer economically productive to the society as a whole - at least no in capacities involving physical labor, though there are certainly exceptions, and mental labor is still a vital part of society and economy.

but in general, when it comes to getting on or off a planet's surface, i still think some variation on a space elevator is the best means. it gets around grandma's vulnerability to high Gs, and it spares the waste of using fuel in the first place. i'd previously advocated the space fountain variation because they don't require super-tensile materials we haven't yet invented/discovered, and because they can be constructed from orbit, down.

a swinging arm space station! A space station with a long swinging arm that rotates at high speed with which ships can dock without having to decellerate after arriving from another world. The arm would have to be long enough so that gravitational forces would not be too high for the passangers (if that is at all possible?) yet maintain high speed to slingshot the spaceship back the way it came.


simply put, that wouldn't work. as soon as the ship docked with the station, the difficulties of doing so at high speeds not withstanding, the space station's orbit would change in the direction the ship was travelling and proportionate to their difference in mass - same deal with a fast-orbiting station. moreover, it'd require constant expendature of fuel to maintain a fast orbit - natural orbital speeds are constant and determined by the mass of the object the satellite orbits around. when something spins around something else (or orbits) the circular motion is actually described physically by acceleration, even though the circular speed is constant. as danielost pointed out, this is because momentum only in a single direction; therefore turning requires energy. the circular speed doesn't increase because there energy doesn't end up in the form of velocity, but in tension (for a rope - in a natural gravitational orbit, the 'tension' force equals the force of gravity between the two objects, which is what keeps the orbiting objects from colliding).

however, liquid breathing is a great topic we haven't touched yet at all - and an important one because without it, the acceleration period on a journey between stars will be long because the maximum acceleration would be severely limited to at most a few Gs. quoth wikipedia:
Liquid immersion provides a way to reduce the physical stress of G forces. Forces applied to fluids are distributed as omnidirectional pressures. Because liquids are (virtually) incompressible, they do not change density under high acceleration such as performed in aerial maneuvers or space travel. A person immersed in liquid of the same density as tissue has acceleration forces distributed around the body, rather than applied at a single point such as a seat or harness straps. This principle is used in a new type of G-suit called the Libelle G-suit, which allows aircraft pilots to remain conscious and functioning at more than 10 G acceleration by surrounding them with water in a rigid suit.

Acceleration protection by liquid immersion is limited by the differential density of body tissues and immersion fluid, limiting the utility of this method to about 15 to 20 G. Extending acceleration protection beyond 20 G requires filling the lungs with fluid of density similar to water. An astronaut totally immersed in liquid, with liquid inside all body cavities, will feel little effect from extreme G forces because the forces on a liquid are distributed equally, and in all directions simultaneously. However effects will be felt because of density differences between different body tissues, so an upper acceleration limit still exists.



i'd like to make a general request. colonizing Mars or any second (or third, or whatever) planet in a system that already has a completely developed planet is an entirely different beast than sending a colony to a new star system. i think it'd be good for the sake of clarity for us all to try and distinguish which we're talking about when, at least when we begin a new line of discussion.

edit: WOW! 10 pages in this topic thread!
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Reply #453 from GalCiv2 Forums Top
simply put, that wouldn't work. as soon as the ship docked with the station, the difficulties of doing so at high speeds not withstanding, the space station's orbit would change in the direction the ship was travelling and proportionate to their difference in mass


sorry i forgot to mention, the space station would be designed to recieve and dispatch spaceships in 1 direction such as a destination planet and Earth. You could build another space station the same at the other planet to throw spaceships to and fro and never have to pay for fuel! except very minor course adjustments necissary because of planitary and or space station orbits.
Reply #454 from GalCiv2 Forums Top
tail lander




think moon lander what did it come down on.
Reply #455 from GalCiv2 Forums Top
sorry i forgot to mention, the space station would be designed to recieve and dispatch spaceships in 1 direction such as a destination planet and Earth. You could build another space station the same at the other planet to throw spaceships to and fro and never have to pay for fuel! except very minor course adjustments necissary because of planitary and or space station orbits.


well, the idea in general could work for relatively small things - cargo shipments between planets - but my point was that the docking process would change the space station's orbit in a way that would mean the station would have to use fuel to stay in a relatively stable orbit whenever it catches or throws a parcel ("for every action..."). i suppose it could work better if you timed separate shipments to arrive and depart at the exact same moment, but that would limit its overall usefullness a bit. just remember, whether or not you use fuel, you still expend energy; that said, not having to accelerate a fuel source is a great means to higher net efficiency.

i was a little thrown off because you initially described these stations as a way to avoid the need to use fuel to decelerate. truth is, you can also use gravity assists to decelerate a craft just as easily as you can to accelerate it. the stations you're describing would probably work best to accelerate shipments into a gravity-assisted trajectory. but the stations would still need some sort of thrusters to maintain their own stable orbits.

think moon lander what did it come down on.


do you mean 'tail' as and ending in time, or as the back end of a design or physiology (the tail end of a book or journey, or the tail of a fish or plane)? the lunar module landed on struts.
Reply #456 from GalCiv2 Forums Top
also, i don't really agree with the grandma premise.


i believe that 1/3 to 1/2 of the population cannot withstand the g forces of a shuttle take off. and at best it only pulls 5 or 6 gs. i don't think i could take it anymore.

as for grandma before daycare if both parents had to work. grandma was usually the babysitter, not always but.
Reply #457 from GalCiv2 Forums Top
the lunar module landed on struts.


and these struts were at the back of the ship until it came in for a landing at which time it turned 90% and landed on its end. or tail. thus only requiring the amount of land that the struts required to land on.
Reply #458 from GalCiv2 Forums Top
well, the idea in general could work for relatively small things - cargo shipments between planets - but my point was that the docking process would change the space station's orbit in a way that would mean the station would have to use fuel to stay in a relatively stable orbit whenever it catches or throws a parcel ("for every action..."). i suppose it could work better if you timed separate shipments to arrive and depart at the exact same moment, but that would limit its overall usefullness a bit. just remember, whether or not you use fuel, you still expend energy; that said, not having to accelerate a fuel source is a great means to higher net efficiency.


Ah ic your point about ballance. You would have to have 2 equal arms in opposite directions. And then there would need to be a counterweight drawn up the arm opposite the spaceship in order to reduce the amount of fuel needed to maintain ballance.
Reply #459 from GalCiv2 Forums Top
super-tensile materials we haven't yet invented/discovered


Carbon nano-fibers are strong enough. The problem is we don't yet have a way to manufacture them en masse into necessary structures.

edit: WOW! 10 pages in this topic thread!


My goal is to beat Frogboy's "Show off your ship designs 2007!" thread.
Reply #460 from GalCiv2 Forums Top
i believe that 1/3 to 1/2 of the population cannot withstand the g forces of a shuttle take off. and at best it only pulls 5 or 6 gs. i don't think i could take it anymore.


what makes you think that so much of the population would be travelling around so much that it's a significant factor? tourism? tourism is a waste of resources.

as for shifting the population around to alleviate overpopulation and move skilled technicians and laborers - some will still have to stay on the homeworld, and i'm sure the selection process would take into account their physical constitution.

beyond that, i don't think that we'll ever have the technology that'd allow 100% of the population to travel space, for a lot of reasons you haven't mentioned. any sort of suspended animation would require chemicals some people might be alergic to. for those who remained awake for long periods of a journey, a skeleton crew at least, a rigorous psychological makeup would be necessary. i'd say the ideal would be low metabolism (uses less food and air) and low body weight (such as with horse racing jockeys). and then there's always phobia.

the only reason i can see that we'll put serious effort into exploiting resources in space is when they become tight here--which means we won't waste them on allowing the middle class to galavant wherever it pleases, at least, not without the kinds of unrealistic and pseudo-scientific technology you'll find in the Star Trek universe.

My goal is to beat Frogboy's "Show off your ship designs 2007!" thread


LOL me too!

Carbon nano-fibers are strong enough. The problem is we don't yet have a way to manufacture them en masse into necessary structures.


fair enough, but the space fountain design still has other advantages. check it out if you haven't yet: WWW Link.

it's biggest disadvantage admittedly is that it has a constant power requirement. but elevating a payload wouldn't require nearly as much additional power the way it would with a traditional space elevator (afterall, the point is to get stuff into orbit, right?). plus, it has a really high "wow-neat!" factor
Reply #461 from GalCiv2 Forums Top
sorry it is usually the wimps and the people who aren't making it at home who colonize. meaning that most of your colonists volunteers would come from that group that can't handle the high Gs
Reply #462 from GalCiv2 Forums Top
at least, not without the kinds of unrealistic and pseudo-scientific technology you'll find in the Star Trek universe.


The only difference between most ficticious science and real science is time!
Reply #463 from GalCiv2 Forums Top
at least, not without the kinds of unrealistic and pseudo-scientific technology you'll find in the Star Trek universe.


The only difference between most ficticious science and real science is time!




we can do almost everything that star trek can.


exception teleport(i have heard this has been done.) and ftl travel
Reply #464 from GalCiv2 Forums Top
we can do almost everything that star trek can.


huh?? not even for startrek 'enterprise'. Wait, try Startreck first contact, Earth, right before The borg and enterprise arrived from the future and your statement has some truth.
Reply #465 from GalCiv2 Forums Top
it's biggest disadvantage admittedly is that it has a constant power requirement.


Couple that with our predicted shortage of resources...

It is certainly an interesting idea, but if I read correctly, the only trade off between the fountain and a traditional elevator is higher energy costs vs. necessitating ultra strong materials. It does seem a little more "sci-fi" though. It's like a giant mancannon.

exception teleport


We have managed to teleport electrons, but thats all (didn't we already talk about this?).
Reply #466 from GalCiv2 Forums Top
sorry it is usually the wimps and the people who aren't making it at home who colonize.


danielost, could you please make more of an attempt to explain your ideas? this statement seems almost offensive to me. my own Scottish ancestors were early american colonists. they fought in a number of wars in Scotland and Britain, securing them a prominent place among the Scottish clans since the 10th century; they were neither wimps nor had trouble making it (it actually wasn't until we were settled in the U.S. that this branch of the clan became mostly working class).

it's one thing to have an opinion, but it's another thing to casually drop it into a conversation using slightly confrontational language and without explaining why you believe something others obviously don't.

The only difference between most ficticious science and real science is time!


time, and money (more specifically, the resources it represents): money is the real qualm i have. i called the stuff in Star Trek pseudo-science, not because the effects are impossible, but because the execution is so convenient and easy for the sake of plot (exactly how many things have navigational deflectors been reconfigured to do?). that's what they call a dues ex machina.

i enjoy Star Trek, but that doesn't mean i think it's very well written most of the time, and it's definately not hard scifi. that's also not to say i think hard SF needs to delve into pages upon pages of technical explanations of every particular facet of technology to be 'hard' - this issue is about maintaining consistency. if those deflectors were really capable of doing so many incredibly different things, i find it hard to believe it wouldn't be part of their operational manual already.

i don't think it's as much an issue for a video narrative. "seeing is believing" seems to apply to suspension of disbelief as much as it does to real life. but in written work, the audience is going to notice (and dislike) things like that far more readily.
Reply #467 from GalCiv2 Forums Top


we can do almost everything that star trek can.


exception teleport(i have heard this has been done.) and ftl travel


To add to the list of exceptions:

Artificial gravity equipped space ships, hand held phasers, phasers in general, anti matter engines, androids, near perfect artificial hearts, VISORS, acrobatic space craft, orbital ship yards, terraforming, tractor beams (usable on any item), force fields, automatic doors that actually work...

Reply #468 from GalCiv2 Forums Top
huh?? not even for startrek 'enterprise'. Wait, try Startreck first contact, Earth, right before The borg and enterprise arrived from the future and your statement has some truth.




where do you think the idea for the cell phone came from. even the size of some are comparable to the new generation badges.


then there is the devise more or less still on the drawing board that can take all of your vitals.

we can build ships in space. ie the international space station or whatever name it has this month.

our computer power isn't comparable but getting there.

Reply #469 from GalCiv2 Forums Top
the only trade off between the fountain and a traditional elevator is higher energy costs vs. necessitating ultra strong materials


nope, missed a couple points. a traditional space elevator could only be constructed from orbit, down, while a space fountain can be built from the ground up or from orbit down. it also can be build from any location on the planet, not solely the equator. finally, it can be built to any height, since the terminal station doesn't need to be in a stable geosyncronous orbit (in face, with some work the height could even be adjusted). finally they're flexible, which means the same principle could be used to support curved structures.

as for power, on earth it at least wouldn't be as much an issue if we get fusion power: we've got plenty of hydrogen for fuel (in the form of water, which can be easily converted to molecular hydrogen and oxygen with current technology). even given breakthroughs in carbon filament manufacturing, i think what would be produced could likely be tied up in other uses, making the fountain a better in terms of net overall resource application.

automatic doors that actually work


except in blooper reels  
Reply #470 from GalCiv2 Forums Top
exactly how many things have navigational deflectors been reconfigured to do


hahahaha yea, and the list goes on!

automatic doors that actually work...



Absolutely! hahahaha.... I wish i had a penny for every time i have had to stop in my stride because the automatic doors at the shops are too slow!! and i'm not even mentioning ones that arn't working properly.
Reply #471 from GalCiv2 Forums Top
danielost, could you please make more of an attempt to explain your ideas?



the puritans were the first Europeans to come here to stay. they were the dredge of English society.

the non wimps that came were the explores. the wimps were the ones that came here to build towns and stay here. they were not going to go home. and i think that when we colonize mars it will be the same way more or less.

when we "colonize the moon" it won't be a real colony. we are planning on using it as fueling station for the rest of the system.

so these "colonists" will be the same to some degree as the explorers and the ones who came here looking for gold.

but to build a society in a new place you need people who are willing to settle down in one place and stay.

as for your family i meant no disrespect. i don't know when they came over. but in the wild wild west it was the non wimps that cleared the land of hazards except for themselves of course. and it was the wimps that built it.
Reply #472 from GalCiv2 Forums Top
hand held phasers, phasers


we have energy weapons just because they haven't been released to the public. where do you think the laser tag guns came from.


what about surgical lasers those are hand held i believe.
Reply #473 from GalCiv2 Forums Top
Artificial gravity equipped space ships


ok we can't do artificial gravity. but we know how to do simulated gravity.
Reply #474 from GalCiv2 Forums Top
but in the wild wild west it was the non wimps that cleared the land of hazards except for themselves of course. and it was the wimps that built it.


i think your confusing wimps with poor people who had no other options but to settle wild lands.

They say necessity is the mother of all inventions, they forgot to mention it is also most definately the mother of all colonisations!
Reply #475 from GalCiv2 Forums Top
i was just think about this


my idea of artificial gravity. an electic magnet strong enough to pull on the iron in your body without tearing it apart. we already use electric magnets strong enough to rip the iron out of your body.

but you wouldn't be able to test this on earth.