Hey everyone, I got inspired and started writing a hard sci-fi story about the first attempt at colonizing a planet outside our solar system, but i'm sort of hung up on what type of ship to use. Here are the essetial "facts" so far: The year is about 2150, i'd like the original crew to be alive when the ship arrives at alpha centauri; maybe 8-10 years ship-time to get there. I would prefer not to resort to things like warp drive or even antimatter if possible. Also, any suggestons on how to deal with artificial gravity? I originally thought a rotating torus would be good, but then realized that if i was accelerating fast, the colonists would be pushed towards the back of the ship as well as down to the floor due to the rotation. So that's an issue. Also any suggestion about shielding and stuff would be helpful. Thanks. :)

Not sure about using Alpha Centauri. Binary system, not suitable I think.

Yes it's binary, actually trinary, but the stars are not in close orbits, theres plenty of room between them for suitable planets. Unless my information is wrong, or course, but i was pretty sure it was just fine.

EDIT: I found a link to a site that shows the orbits of the stars compared to their habitable zones.

http://www.solstation.com/orbits/ac-absys.htm

Oh, that's very cool, thanks. :)

But do the gravities from each not cause problems within the habitable zones of each system?

There are several theoretical systems for propulsion. The time frame allows for speculation for technological advancement. Your propulsion system will determine your ship design, and both will depend upon the physics of your universe. Bare in mind that physics is also open to speculation. A search (offline as well as online, see your local library)will reveal some current theories and designs, and a healthy dose of sci-fi will help you see how the good authors work around problems. REmember the socail and political aspects, these will round out the story. Have fun and good luck!

I read somewhere that the Saucer shape is in fact the best way to build a space ship.

I'd go for something like those old roman galleys. They were cool.

Anything with guns bigger than Wales is good enough for me

Basically, a sphere is the ideal shape for the cabin part. Its the lightest and strongest way to build it to be pressurized. Various stuff, cargo not needed inflight, engines, telescopes, antannas, might then be placed in a grid framework on the outside of the sphere.

Gravity: You are envisaging 8-10 years transit time. That means that the ship will travel at a significant fraction of the speed of light, so either you have an acceleration phase at start and a decelration phase at arrival, and in the meantime use rotation for gravity, or else, you might envisage some fairly weak but durable propulsion system (an ion drive or something like that) so you accelerate halfway out there, then turn the ship about and decelerate the rest of the way, all at a rate giving a comfortable gravity.

Now I'd suggest a visit to the library to sort out the math of the trip; accelerating at 1G for two lightyears, then decelerating for another two, which max speed will that give you, how long will the journey then take, subjectively to the crew of the ship, and objectively (and longer) to the people on Earth? Probably, you can get that ready-made as several authors have proposed such a travel mode.

Have fun, Hans

Nova

I originally thought a rotating torus would be good, but then realized that if i was accelerating fast, the colonists would be pushed towards the back of the ship as well as down to the floor due to the rotation.

A rotating torus IS the best idea. Acceleration will be an issue with any ship. Rotation will not.

Actually, a rotating thorus is not easy to do in practice, unless it is very large. The idea sounds simple, but it will easily become unstable as occupants move around inside it. Of course, various stabilizer systems can be added to overcome this.

Hans

mrc hans

That's the idea. The torus would have to be at least 1/2 mile wide. Something along the lines of this:

http://www.l5news.org/graphics/torusinterior-800.jpg

http://www.l5news.org/graphics/toruscutaway-800.jpg

Imagine trying to accelerate something like this...*shudder* Or what about in-orbit assembly on such a scale... Hmm, it would probably have to be done on and launched from the Moon or something.

Also, at significant fractions of lightspeed, this sort of a huge yet lightweight design would be murdered by space dust. It would need kilometer-thick shields to absorb near-nuclear energy impacts from tiny particles. Which might "slightly" add to its aleady mind-boggling mass.

I think for interstellar expeditions of any real scale one would have to go slow. Which means the only real option is generational spaceships or alternatively a genetically enhanced/cybernetic/robotic crew that can survive and function for thousands of years.

Unless you want to get into gee-whiz speculations about energy shields a-la Startrek or something.

The best system is a tear drop shape, accelerated at 1/2 G for half way then reverse thrust and reverse orientation.

Levels would be perpendicular to the direction of travel. The propulsion system should rely of magnetohydrodynamical principles manipulating the magnetic ( and electric where appropriate) lines of force throughout the Universe.

Other useful means of propulsion, depending upon the situation, are inertial drive (basically stable antigrav) and / or a vortex drive( ? Podkletnov effect) which are ideal for terrestrial work.

If the crew hibernates, then you don't need gravity, and the mass of the support system will be less than those big wheels, which are more space colonies than ships. Have the crew take watch shifts from 6 months to 1 year in lenth. Much more desirable than hoping the computer doesn't malfunction. The problem with this is that so far FTL travel is more likely than such a hibernation system. If you get much biggerthan the ISS, than bringing asteriods into earth orbit to use for building materials would probably be more practical than having to launch the stuff into space. Easier on the environment too.

Those giant space-wheels look most fascinating, but I dont believe in them, especially the one with the long river/lake in it has an inherent stability problem: Suppose it gets ever so slightly misaligned (I'm talking fractions of millimeters), then gravity will be just a little bit higher somewhere along the perimeter, so a little more water will collect there, offsetting the balance a little more --- etc. etc.

There is also the safety issue: It would have to be sectioned, otherwise a meteorite hit would be disastrous. For a space colony (or a generational voyager), I would envisage a ring of spheres, like a pearl necklace, possibly even with flexible joints.

In this way problems (leaks, fires, infectious diseases, even revolts) could easily be isolated. In the worst case, a "bead" could even be jettisoned.


Mmmm, hey! What a scene fo an SF novel!

Hans

Thanks for the input everyone. I've sort of lost momentum on this story, but eventually i might start it again and this info will be helpful. Either way, its a very interesting topic. :)

I am new to the forum so i am a bit behind but this thread caught my eye so i figured I would add to it. One torus habitats, stations, and ships can be stable water will always collect in the area of strongest gravity but doesn't mean it can't be pumped elsewhere. Anyhow reducing the gravity or making it a true ship and not the fancy space wasteful tubes like the classic torus stations will make it more practical. you could create a torus station ship that was only 500-1000 meters in diameter and have enough room for 1000-10000 people and provide recycling of materials. The ship could use fusion as its power source. Or it could use a particle beam driven magnetic plasma sail if you don't want to have to carry all of your fuel with you. To get there within the crews lifetime would require traveling at about 50% of light speed which means you could get to the nearest stars within 50 years or less.

Actually a torus wouldn't be the ideal shape several 1km counter rotating spheres would work. with ice for debris shielding in front perhaps mixed with several layers of mylar and kevlar type materials *Ie bullet proof materials* lasers to deflect larger particles from your path and your set. Now a magnetic plasma shield is possible using solenoids so you ahve your radiation shielding right there, also such a radiation shield can be used as a break in the target star system.

Well there are my 2 cents worth.

How about we just say this... even in the next 150 years, I doubt that the technology would be avalible for all the ideas presented. But anyway, the thing is, interstellar travel is so incredibly far fetched using "Speed" as a way of traveling that I believe it will never happen.

Think about it. even if you went 99.9% the speed of light, It may seem to take only say a few hours to get to Alpha Centauri, BUT 4.3 years has pased on earth. So, by the time you get back, 8 1/2 years has passed. Now imagine a star 100 lys away, or the center of the milky way 100,000 lys away. Not to mention problems getting to that speed, not being obliterated by space dust, design problems, ect.

So REALISTICALY, wormholes are like the only way that I can Invision our civilization ever even attempting to travel to another star. And that technology is like 1000 yrs away if it even exists at all.

Later,
T:rolleyes:

To get to alpha centauri in about ten years you would have to travel about 23000 kilometers per second, maybe with future technology it would be possible, but definitely not nowadays.

The Bussard Ramjet is one good possibility. I think there is some debate if interstellar hydrogen density is high enough to provide fuel for the ramjet. However if it is workable then it has some other nice features since the magnetic fields would provide some shielding for debris.

There isn’t anything wrong with antimatter either, it would provide the highest theoretical energy density for fuel.

But whatever you use, the idea of sending thousands of people on this journey is unlikely. You want to average about .4 C and if you use the constant acceleration model that means your peak velocity would be much higher than that. To move a thousand people with all the required food, air, water and other supplies would require staggering energy expenditures. You’d probably have to have an antimatter asteroid or two to do it.

A colony ship?

Basically a bic rotating cyllinder stuck to a dome at either side. One dome would be a scoop for hydrogen collection, the other would be for exhaust funneling.