Propulsion Concepts

[ÑóẊîöʼn]

I'm currently in the process of 'fleshing-out' an interstellar colony ship. It will have a destination as yet undecided, be built with technology that's attainable in the next 50-100 years, and carry colonists,(Around a million to ensure a stable society) their equipment, and their means of production (Both food and manufactured goods)

As part of the project, I have to decide on a method of propulsion, which I'm going to discuss here with you.
I will present a number of propulsion methods suitable for interstellar travel, presenting various pros and cons.

Nuclear Pulse - Approx. 5% Lightspeed

Summary:
A spacecraft powered by the shockwaves of nuclear bombs!

PROS:

Easily controllable - you can vary the rate of bombs being dropped
Large-scale operations are made easier by using stronger bombs.
When there are no nations left, this would be a perfect way to get rid of the nuclear stockpiles.

CONS:

It leaves a trail of nuclear explosions, so it would have to start it's journey at the edge of the solar system
It's quite slow.
Bombs could be stolen and misused during construction

INERTIAL CONFINEMENT FUSION - 15% Lightspeed

Summary:
Inertial confinement fusion (ICF) requires high-power lasers or particle beams to compress and heat a pellet of fusion fuel to fusion ignition conditions. In operation, the pellet of fusion fuel (typically deuterium-tritium, D-T) is placed at the locus of several high-power laser beams or particle beams. The lasers or particle beams simultaneously compress and heat the pellet. Compression of the pellet is accomplished by an equal and opposite reaction to the outward explosion of the surface pellet material. Heating of the pellet results from both the compression and the inputted laser energy (or particle-beam kinetic energy). The pellet's own inertia is theoretically sufficient to confine the plasma long enough so that a useful fusion reaction can be sustained; hence this fusion reaction is inertially confined.

PROS:

Utilises very powerful fusion power
Safer than Nuclear Pulse
Faster than Nuclear Pulse

CONS:

Dueterium pellets may be expensive in a socialist society, and difficult to manufacture in a communist/anarchist society
Lasers Eat a lot of power
Seemingly small power-to-weight ratio (Scroll down to Daedalus design to see how)

Interstellar Ramjet - 30% lightspeed, with any luck

Summary:
Basically, the ship consists of a giant scoop to collect all the extremely tenuous hydrogen ions that drift in deep space, and burn them for fuel

PROS:

Fuel is not carried onboard, meaning thrust-to-weight ratio becomes meaningless
It's fairly uncomplicated, and thus easy to repair.
Easy to build for such a fast vehicle

CONS:

We don't know just HOW rarefied the hydrogen is; it could be practically nonexistent
It will need a running start up until 4% the speed of light before the amount collected becomes useful.
Electromagnetic gathering net may need a lot of power.

Matter/Antimatter Annihilation - 50% Lightspeed

Summary:
Hydrogen and anti-Hydrogen are annihilated in a chamber and the resulting reaction is forced down a nozzle to produce thrust (As with chemical rockets)

PROS:

Powerful, perhaps more so than nuclear reactions
Number of designs at our disposal
Hydrogen is abundant

CONS:
Anti-Hydrogen difficult to manufacture
Lots of radiation produced - Heavy shielding required
Antimatter has to be kept seperate from ANY normal matter

Fusion/Matter-Antimatter Hybrid - 75% Lightspeed (Wow&#33

Summary:
A single Antimatter engine surrounded by up to eight ICF engines. The combined thrust will be very high indeed.

PROS:

Extremely short journey times to nearest stars.
Possibly a single generation could crew such a ship.
A simple combination of technologies.

CONS:

Possible temporal anomalies due to high speed
Overheating may be a problem
Structural concerns at such high speeds.

The last one sounds promising, but there may be other problems associated with it

Any thoughts?

[cubist]

how much would all that cost and what would it do for our society mate?

sounds good but realistically is it a.possible and if so is it b. plausable

[ÑóẊîöʼn]

how much would all that cost

You're putting a price on the future of humanity now?

and what would it do for our society mate?

Oh, only prevent the extinction of the entire human race. That's all. Besides, we've always crossed vast gulfs before.
Now I'm just waiting for the fashionable nihilists to say 'so what? The human race gone will be a good thing!' Well I don't share your view. Go write some suicidal poetry instead of bothering me!

sounds good but realistically is it a.possible and if so is it b. plausable

This sounds like the typical answer to Communism.

I did my research. I said in my post that these would be achievable with technology available now or within the next 100 years.
Did you read the entirety of my post? or did you just skim it and say 'it's not possible' because you felt you needed to say something rather than keep quiet, as opposed to reading it carefully and providing an intelligent suggestion or rebuttal?

-NoX

[cubist]

lol

save thehuman race, why? let nature kill it out. i don't want the selfish bastards that be, to be saved we won't go only the rich and powerfull will ever be saved if that happens.

[ÑóẊîöʼn]

You seem to be making the assumption that extra-terrestrial colonisation will occur while class society exists. It can't because it's not profitable.
There won't be any rich and powerful bastards to save, but you will have to have relevant knowledge and a degree of fitness in order to go on a trip, although it won't be as strict as you think.

Besides, one of the things that makes the human race so special is it's refusal to allow nature to simply steamroller over them. If we let nature kill us then we're no better than animals.

[cubist]

great un-natural selection processes, i don't like it its wrong who wants to save the selfish humans anyway if we fuck the world up we shouldn't fuck anyone elses. its unfair to leave people to die and its wrong to try and play god by selecting who can live and who gets to die, why don't you just cut off the balls of stupid people now and you may not have to sav the world later.

[ÑóẊîöʼn]

Unnatural selection for humans has a bad name thanks to the eugenics carried out by the Nazis.
It isn't all bad. The nazis went the wrong way about unnatural selection, they wanted to effectively create a master race. Wrong. Apart from minor physical differences, there is no such thing as races.
The colonists must be taught that they are performing a vital duty, but just as vital as every other human is doing.
What's wrong with picking the smartest, fittest humans (Regardless of ethnicity) for an interstellar mission?

i don't like it its wrong who wants to save the selfish humans anyway

The selfish humans want to save the selfish humans. anyway, if humans are so selfish how come things like charities and Communism exist? If that's selfish it's very generous.

its unfair to leave people to die and its wrong to try and play god by selecting who can live and who gets to die,

With any luck, the humans left on earth won't die out for at least a million years, by that time it's reasonable to assume they will have developed some sort of faster-than-light travel. So they can simply move if life on earth becomes unbearable.
What's wrong with playing god? If we can beat Him at His game, let's play.

anyway if we fuck the world up we shouldn't fuck anyone elses.

It's our fundamental right as a species to survive. If that means trashing a few planets on the way, so be it.

why don't you just cut off the balls of stupid people now and you may not have to sav the world later.

Because THAT is hitler-style eugenics, a big mistake. and killing off the 'stupid' people may be harder than it seems. how do you determine whether someone is stupid? IQ tests? they're highly unreliable.
Also have you heard of 'idiot savants'? People who can find the square root of 98724542 in under a second or work out what day christmas was 23597 years ago, but can't for the world tie their own shoelaces together? Such people are useful, even if they need help with their shoes.

See? the people left behind will have time to work on something faster, while the colonists can pave the road for the people back home.

It's a good deal all round.

-NoX

[SittingBull47]

I've read that if we develop stronger ships and slightly faster propulsion, we can use black holes to sling into a hyper-fast orbit. I think it deals with skimming the sides of the black hole, going around in circles, and once the ship gets to a certain point they could punch the propulsion and the momentum would fling them into space at ridiculous speeds. I think it's a very natural approach to such a high-tech plan.

[ÑóẊîöʼn]

Good idea, but finding a nearby black hole would be a problem.

I prefer 'slingshots' for altering the course of ships, not for actual launch. The reason being is that you have more control over an engine; make a mistake with an engine and you can correct it it, make a mistake with a slingshot launch and you're buggered.

A slingshot approach to a star would be useful if a ship wanted to return home, just use the star's gravity field to make a U-turn, although I admit that a situation that necessitates returning home would be a rare one indeed...

Here's a something for you to chew on:

Whether we can go faster than light (FTL from now on) is actually undetermined, depending on what model of time the universe follows; if it follows the einsteinian model of time 'being different everywhere', then FTL is impossible. (It would break the laws of causality) If it follows the Newtonian model of there being a basic, underlying timeline that is the same everywhere, then FTL travel is does not break laws of causality.
Think that one over. It may be that case that it's actually a combination somehow

-NoX

[cubist]

i see, i don't like it sounds very fascist and american. you said yourself you would have relevant knowlege which rules out a large collection of people. how ever it would be the pefect place to initaiate true communism each family has a job to do something inside the settlement. very utopian in its possiblilties. but i sense that something so beautiful will be used for bad not good.


ok well put it like this humans due to the effects of the social/economic systems inplace where economy controls the social have become greedy and selfish, yes charity exists but it doesn't cure the issue of why we need the charities, it is relief for the pain not a solution for the illness if you like. the solution would be helping the homeless cancelling third world debt and sharing our hoards and stock piles of food

[ÑóẊîöʼn]

i see, i don't like it sounds very fascist and american. you said yourself you would have relevant knowlege which rules out a large collection of people.

We can give more people the relevant knowledge. I can't think of many people who have a degree in Deepspace Engineering.

but i sense that something so beautiful will be used for bad not good.

That's why it should happen under classless society, as there will be no ruling class to abuse the facilities

ok well put it like this humans due to the effects of the social/economic systems inplace where economy controls the social have become greedy and selfish, yes charity exists but it doesn't cure the issue of why we need the charities, it is relief for the pain not a solution for the illness if you like. the solution would be helping the homeless cancelling third world debt and sharing our hoards and stock piles of food

The mere fact that charities exist indicates that selfishness can be manipulated into benevolance, if we can provide relief we are capable of providing the cure.

-NoX

[cubist]

we are indeed comrade unfortunately capitalism prevents this from happening

[redstar2000]

Some other considerations that need to be taken into account...

It may be that there is just enough "debris" in interstellar space to enforce a practical "cosmic speed limit" of 5 to 15% of the speed of light.

There is a "slow" version of interstellar travel that is quite practical; instead of "building" a spaceship, take a moderate-sized asteroid: hollow it out for living quarters, and eject the mass...you will, by Newton's third law, begin to move.

It would be a "multi-generational" ship...even the nearest stars would take hundreds and perhaps thousands of years to reach. But it's not as if we were short of time.

Which raises another point; one reason why the stars seem so far away is that our own life-spans are so short. People may be reluctant to spend 90% of their lives in a one-way trip to the nearest star...but suppose we could reasonably count on a life-span of 500 or 1,000 years? Perhaps a two hundred year journey would not seem so daunting...?

There is a huge (by earthly standards) "plume" of anti-matter near the center of our own galaxy (about 30,000 light years away)...no one knows what is causing its appearance. Many centuries from now by techniques that are presently unimaginable, we humans may possibly "mine" this "resource"...and indeed reach speeds of 75% of the speed of light.

It's my understanding that "time dilation" (time on the spaceship "slows down" compared to time elsewhere) doesn't really start to "bite" until you get upwards of 90% of the speed of light.

But I do recall reading the late Isaac Asimov's calculation: at 99% of the speed of light, a journey to the nearest galaxy (about three million light years) would take about 52 years, ship's time.

Three million years would pass back on earth, but the ship's crew would age 52 years, that's all.

If we can just make it through the trauma of class society and its final centuries, we have a grand future to look forward to.



The Redstar2000 Papers
A site about communist ideas

[ÑóẊîöʼn]

It may be that there is just enough "debris" in interstellar space to enforce a practical "cosmic speed limit" of 5 to 15% of the speed of light.

I somehow doubt there is anything more substantial than dust or gas between the stars... maybe the occasional stray planet or comet but certainly not enough of them to present a significant danger to speeding colonists...
It would be interesting however to see the effects of an Interstellar Ramjet hitting a dust cloud or a nebula... probably catastrophic.

There is a "slow" version of interstellar travel that is quite practical; instead of "building" a spaceship, take a moderate-sized asteroid: hollow it out for living quarters, and eject the mass...you will, by Newton's third law, begin to move.

Admittedly I had a less... spectacular vision for this sort of thing.
I thought that this might be more useful for asteroid mining; seperate the matrix and useful material, and use the matrix as fuel to propel the asteroid, and hopefully by the time you reach Earth all the fuel has been used up and you have nothing but raw materials for building your space constructs, or even build things on Earth...

It would be a "multi-generational" ship...even the nearest stars would take hundreds and perhaps thousands of years to reach. But it's not as if we were short of time.

It is important that whatever society we place on such a ship, that it ought to be a stable one.
Unfortunately, a quasi-military organisation with respect for the chain of command is the most stable, but also happens to be the least inventive.
Even if the space-going society is as egalitarian as ours on earth, they will be well and truly isolated for a very long time, meaning that quirks may develop and social turmoil may occur. (We should do our best to ensure the damage is minimalised)
There are not only technological barriers to overcome, but social and psychological ones as well.
There is also the danger that the first generation on such a ship may get homesick... this is the last thing we want to happen, as homesickness will inhibit production and cause emotional problems and may even jeopardise the mission.
I think the best solution is to raise the first generation on the ship, before launching. That way all they'll have ever known is the ship. It may sound cruel, but you don't know what you're missing if you've never experienced it.
This is not to say that conditions on the ship will be harsh or spartan; quite the opposite. Creativity thrives, especially when one isn't looking for the next meal or doesn't have discomfort distracting them.
There is also the issue of population size; too small and the gene pool is limited; too large and things become unmanageable.

Which raises another point; one reason why the stars seem so far away is that our own life-spans are so short. People may be reluctant to spend 90% of their lives in a one-way trip to the nearest star...but suppose we could reasonably count on a life-span of 500 or 1,000 years? Perhaps a two hundred year journey would not seem so daunting...?

Ah yes, one of the great human searches; long life.
There are many ways to go about this, as I am sure you are aware. The first and perhaps the most difficult way is to actually extend the lives of humans, by way of the so-called 'methuselah gene' named after a biblical character who allegedly lived for 900 years.
Study of long-lived creatures such as tortoises may help us, but in the end I think a greater understanding of what precisely happens when we get old is a must. From what I know, it seems that all the bodies cells are replaced at least once in your lifetime, except for certain types such as brain cells, which probably explains senility. It seems there is a limited amount of times we can replace our bodie's cells, exactly how many times varies of course, as our nails grow almost constantly and our liver cells are replaced once every two years (I think)
There seems to be something in our genes that says 'create this many replacement cells then stop' if perhaps we could alter that script, perhaps make it say instead 'keep replacing as many cells as needed' we could be on our way to creating our own secular Methuselahs...
Another approach would be perhaps less handsome but probably more achievable; that of cyborging.
As we get old, bones become brittle and break, our heart becomes stiffer with age (And clogged up too&#33
and various other organs give up the fight. Except in most cases, for the brain. since we use a very small percentage of it in our entire lifetimes, indicating that the brain can be used for a lot longer than we usually do.
At the moment it's possible to link up human nerves to circuitry and let the brain give orders to the circuits, but it's very crude; you have to become acclimatised to what happen when you stimulate nerves. For example what was previously to you a movement for clenching the fist suddenly becomes, with your new arm, a movement for extending your thumb.
While it's doubtless that techniques will improve with time, adapting to a new cyborg body could be a disorientating experience.
Their is also the issue of the senses. At the moment we can get cameras that have human-eye quality, but they are a lot bigger tha the average eye. But as miniturisation progresses, we can scale down until we have a size we like.
Touch is a simple matter of having an appropiate mixture of heat, pressure and warning (Pain) sensors.
We even have smell detectors, although the qualia ('how things feel&#39 may be vastly different. You may be able to detect the presence of H2SO4 haze or Ni3O2 particles in the air, but you won't be able to smell things in the same way as biological humans do.
Taste is related to smell, but again, precisely how things feel may be different.

There is a huge (by earthly standards) "plume" of anti-matter near the center of our own galaxy (about 30,000 light years away)...no one knows what is causing its appearance. Many centuries from now by techniques that are presently unimaginable, we humans may possibly "mine" this "resource"...and indeed reach speeds of 75% of the speed of light.

I've heard theories that it's coming a vast black hole in the centre of the galaxy, but don't quote me on that.

If we can just make it through the trauma of class society and its final centuries, we have a grand future to look forward to.

That's why I'm a communist; I want to leave something better than an inheritance tom my children, or at least someone's children.

-NoX