Colonized Interstellar Vessel: Conceptual Master Planning

Void · 2014-06-12 10:15:44

Depends upon your likes, and such. However, I think a humble beginning is not unwise.

If Earth local telescopes have not progress enough by then, then the Oort cloud may supply an alternate path to discovery:

http://www.popsci.com/category/tags/ver … rferometry

http://asri.technion.ac.il/space-interferometry/

2 To 10 settlements there could create quite a large interferometric telescope for peering at Alpha Centauri.

And it would also create up to 10 nation states, civilizations.

Then knowing your target, hopefully finding an eliptical object in orbit of Alpha Centauri to connect with upon the completion of the first interstellar flight.

JoshNH4H · 2014-06-12 11:15:23

It's also worth going to the solar focus, because that allows you to use the Sun as a lens to see faraway objects. If you're going to put a lightsail somewhere, that would be the place.

Tom Kalbfus · 2014-06-12 11:35:46

Of course you have to pick your objects with care. If you want to look at Alpha Centauri, you have to put a probe on the opposite side of the Sun to get a focus on that target. You would "aim" your gravitational telescope by moving the space probe around. If you want to track a particular planet, you'd have to keep the probe opposite from the Sun from that planet, so it had better be an interesting planet to justify the cost. I think if your going to colonize the Galaxy, you can't do better than Von Neuman probes and having a generation ship follow the wavefront outward from the Sun.

Antius · 2014-06-13 06:37:17

Interesting concept and I have enjoyed reading the responses. When discussing the possibility of interstellar flight, there appear to be too many variables and unknowns to reliably choose a ‘best’ approach. But we can speculate on the most probable options as we see them today.
Who would fund and carry out such a voyage and why? What would their resource base be? What technological change can be expected between now and then?
If we are talking about a technologically challenging mission, funded by a large population, then a suitable motivation is difficult to find. A sudden Earth-bound disaster is a possible motivation, but in most cases it would be cheaper and easier to adapt to the problem here on Earth. If evacuating the Earth were truly necessary, it would be easier to colonise another part of our own solar system, rather than conducting a century’s long interstellar voyage. Using Orion type ships, we could feasibly transport a large part of the Earth’s population to Mars if we really had to.
A sudden increase in the luminosity of the sun would probably persuade most of the population to leave. But no such event is foreseeable. Again, there are easier and much closer refuges in the outer solar system. A nearby supernova or gamma ray burst would certainly provide sufficient motivation to leave the Earth. But again, it would probably be easier to take shelter within our own solar system; as such an event would last for days not years, and it would be a case of hiding under a mile of ice and then trying to recolonize the solar system afterward. There would appear to be no hope of outriding the radiation wave from such an event and lethal ranges run into dozens of light-years, so escape over interstellar distances would require very long lead times.
The only motivation that really fits is a group of pioneers attempting to set up a new society. Resources available for such a venture are unlikely to be abundant. It is hard to foresee even a wealthy space faring civilisation sanctioning the construction of trillions of tonnes of tsar bombs to propel such a mission. Far more likely, the pioneers will be a few thousand misfits, cobbling together little bits of spare cash and building spaceships in their proverbial backyards. How does that affect mission scenarios? Travelling fast is expensive. Building large ships that travel fast is even more expensive. Building enormous ships that travel at a large fraction of the speed of light would strain the resources of even the largest pan-solar society.
Most likely we are talking either relatively small ships travelling at modest speed, or very large natural bodies travelling at very low speed. Mag-sails and solar sails would appear to be the most technologically easy high speed propulsion system.
One can imagine a mag-sail being used to deflect an asteroid or Kuiper Belt Object onto an elliptical orbit with close approach to the sun, over a period of many years. A combination Jupiter gravity assist and mag-sail would then fling it out of the solar system at a speed of perhaps 10-100km/s. Journey times would be long (tens of millennia), but by the time it arrived, the initial small population (1000?) would have grown into a society of tens or hundreds of millions of people, capable of settling the new planetary system as a mature society. Fission could provide power initially, until the society had reached a sufficient level of organisation to build fusion reactors.
A smaller ship might attempt a close pass to the sun, before unfurling a solar sail and accelerating to 1000km/s. A-centauri would then be 1500 years away. The society would need to adapt to living in a relatively confined space with limited resources for a very long period. Not an easy prospect, but could it tolerably be achieved?

Void · 2014-06-13 08:15:26

Without rude intent.

Other societies contain the descendants of restless peoples. Perhaps North America, Austrailia, etc.

I would think that with the foundations in place interstellar travel could be an occurance for parts of the human race.

The foundations might start with Mars.

https://gsa.confex.com/gsa/2013AM/webpr … 32930.html

http://www.engineeringchallenges.org/cms/8996/9079.aspx

If Mars did have flowing water, then it is reasonable that Lithium salts have been disolved from the general rocks, and deposited as evaporates in certain locations. Previosly it was mentioned that Mars appears to have 5 times the heavy water concentration that Earth does. All of this contributes to the notion that for energy Mars might like Fusion.

As for Lithium elsewhere in the solar system, perhaps Ceres has lithium in the surface deposites? Perhaps it had an ocean and disolved Lithium from the rocks, and then as the outer layers of ice evaporated, it left behind clay like deposites which might contain lithium? Maybe Ceres has concentrated heavy water as well?

Anyway supposing that fusion rocket propulsion made the solar system accessable out to Pluto, then there would almost certainly be some small groups that would choose to extend to objects out to the Oort cloud. By then those humans would be adapted to that environment, and would not think it strange to jump to another Oort cloud around an adjacent star.

Although it is not confirmed some speculation would have it that the Oort clouds go all the way out. That is Alpha Centauri would occasionally exchange objects with Sol. In that case there might not have to be a classical high speed crossing over light years of distance, but simply a constant even progression.

Last edited by Void (2014-06-13 08:16:14)

Terraformer · 2014-06-13 08:16:09

Unless, of course, cheap fusion is achieved. From there, it's not far to fusion rockets, and then the possibility emerges of a small group acquiring a fusion rocket capable of a few percent of the speed of light.

Or, a wealthy group constructing a beamed power system, and selling beam time to groups wishing to settle other stars.

Void · 2014-06-13 08:17:50

I think that fusion rockets will come first.

JoshNH4H · 2014-06-13 09:58:46

Antius, what's your take on my calculations suggesting it would be nearly impossible to get travel times down to 1500 years to another star using solar sails?

GW Johnson · 2014-06-13 11:22:23

Hmmmm.

There is one other forgotten propulsion concept that might apply to interstellar travel. That would be the Bussard ramjet made famous in Larry Niven's book "Protector", part of his "Tales of Known Space" series. You would need fusion rocketry to get you up to ramjet takeover speed, which speculation has at somewhere near half lightspeed. But, since it scoops up interstellar matter (largely hydrogen), it is not limited by mass ratio. A gigantic strong properly-shaped magnetic field scoops up and compresses the hydrogen to the fusion point, then also controls the expansion of the helium product to achieve lots of thrust.

Theoretically, it can move at very close to lightspeed. Faster if you do not believe the "lightspeed limit" is real. The missing technologies are (1) control of very strong AC (oscillating polarity) magnetic bottles hundreds to thousands of miles in dimension, and (2) controlled magnetically-confined thermonuclear fusion of ordinary hydrogen w/o deuterium or tritium.

The other possibility is that somebody finally invents a Star Trek warp drive, and a way to navigate when moving faster-than-light.

GW

JoshNH4H · 2014-06-13 11:36:05

It's my understanding that later calculations have showed that the Bussard ramjet wouldn't be able to exceed the speed of its exhaust (~.12 c) because in the case of the ions being decelerated the decrease in velocity would show up in non-recoverable drag.

I don't understand plasma physics, so take it as you will.

Terraformer · 2014-06-13 15:55:52

Perhaps an antimatter ram augmented interstellar rocket could reach close to the speed of light...?

Or a "Macron beam", of laser (or maser?) accelerated sails, which are vaporised and used to propel a magnetic sail. Yes, to push a small craft at even a low acceleration is going to require terawatts of power, but perhaps a rich enough corporation could afford to build such a system and charge for it's use.

At the moment though, I think fusion rockets - perhaps ram augmented ones - are the most likely, followed by some kind of beamed system. We're going to need fusion anyway, unless you're ragtag bunch of misfits can get hold of sufficient uranium or thorium for the trip - and if they can't build thermonuclear bombs, how are they managing that..?

Of course, if White is right about quantum vacuum thrusters, then we can reach relativistic velocities with fission power... complete with all the problems that a reactionless (well, not *technically*...) drive entails...

Tom Kalbfus · 2014-06-14 00:46:08

Antius wrote:

Interesting concept and I have enjoyed reading the responses. When discussing the possibility of interstellar flight, there appear to be too many variables and unknowns to reliably choose a ‘best’ approach. But we can speculate on the most probable options as we see them today.
Who would fund and carry out such a voyage and why? What would their resource base be? What technological change can be expected between now and then?
If we are talking about a technologically challenging mission, funded by a large population, then a suitable motivation is difficult to find.

What if the large population that funds it goes on the trip?
In my example a generation ship takes 2000 years to travel 63 light years, there is no benefit for the people who stayed behind and sent it, the only benefit is for the population that went on the trip.

Antius wrote:

A sudden Earth-bound disaster is a possible motivation, but in most cases it would be cheaper and easier to adapt to the problem here on Earth. If evacuating the Earth were truly necessary, it would be easier to colonise another part of our own solar system, rather than conducting a century’s long interstellar voyage. Using Orion type ships, we could feasibly transport a large part of the Earth’s population to Mars if we really had to.

When do you buy Life Insurance? Do you only buy life insurance when you are sure you are going to die by a date certain, and if that was true, what company would sell you the life insurance policy?

So your thinking perhaps Russia launches its missiles and we launch our and the missiles will take about 20 minutes to reach their targets and in that amount of time, we can build generation ships and send them off to the stars to save the bulk of humanity from nuclear war? What do is send out a generation ship just in case something bad is going t happen, you don't have to know exactly what is going to happen and when to prepare, and if doomsday doesn't occur, it turns out to be a small investment for the human race, just as buying a Life Insurance policy is for an individual.

Antius wrote:

A sudden increase in the luminosity of the sun would probably persuade most of the population to leave. But no such event is foreseeable. Again, there are easier and much closer refuges in the outer solar system. A nearby supernova or gamma ray burst would certainly provide sufficient motivation to leave the Earth. But again, it would probably be easier to take shelter within our own solar system; as such an event would last for days not years, and it would be a case of hiding under a mile of ice and then trying to recolonize the solar system afterward. There would appear to be no hope of outriding the radiation wave from such an event and lethal ranges run into dozens of light-years, so escape over interstellar distances would require very long lead times.
The only motivation that really fits is a group of pioneers attempting to set up a new society. Resources available for such a venture are unlikely to be abundant. It is hard to foresee even a wealthy space faring civilisation sanctioning the construction of trillions of tonnes of tsar bombs to propel such a mission. Far more likely, the pioneers will be a few thousand misfits, cobbling together little bits of spare cash and building spaceships in their proverbial backyards. How does that affect mission scenarios? Travelling fast is expensive. Building large ships that travel fast is even more expensive. Building enormous ships that travel at a large fraction of the speed of light would strain the resources of even the largest pan-solar society.
Most likely we are talking either relatively small ships travelling at modest speed, or very large natural bodies travelling at very low speed. Mag-sails and solar sails would appear to be the most technologically easy high speed propulsion system.
One can imagine a mag-sail being used to deflect an asteroid or Kuiper Belt Object onto an elliptical orbit with close approach to the sun, over a period of many years. A combination Jupiter gravity assist and mag-sail would then fling it out of the solar system at a speed of perhaps 10-100km/s. Journey times would be long (tens of millennia), but by the time it arrived, the initial small population (1000?) would have grown into a society of tens or hundreds of millions of people, capable of settling the new planetary system as a mature society. Fission could provide power initially, until the society had reached a sufficient level of organisation to build fusion reactors.
A smaller ship might attempt a close pass to the sun, before unfurling a solar sail and accelerating to 1000km/s. A-centauri would then be 1500 years away. The society would need to adapt to living in a relatively confined space with limited resources for a very long period. Not an easy prospect, but could it tolerably be achieved?

Tom Kalbfus · 2014-06-14 00:48:35

JoshNH4H wrote:

It's my understanding that later calculations have showed that the Bussard ramjet wouldn't be able to exceed the speed of its exhaust (~.12 c) because in the case of the ions being decelerated the decrease in velocity would show up in non-recoverable drag.
I don't understand plasma physics, so take it as you will.

The higher the velocity of the propose starship, the lower its plausibility It does us little good t wait for a Bussard Ramjet if humanity ends before it is developed!

Tom Kalbfus · 2014-06-14 00:50:30

Terraformer wrote:

Perhaps an antimatter ram augmented interstellar rocket could reach close to the speed of light...?
Or a "Macron beam", of laser (or maser?) accelerated sails, which are vaporised and used to propel a magnetic sail. Yes, to push a small craft at even a low acceleration is going to require terawatts of power, but perhaps a rich enough corporation could afford to build such a system and charge for it's use.
At the moment though, I think fusion rockets - perhaps ram augmented ones - are the most likely, followed by some kind of beamed system. We're going to need fusion anyway, unless you're ragtag bunch of misfits can get hold of sufficient uranium or thorium for the trip - and if they can't build thermonuclear bombs, how are they managing that..?
Of course, if White is right about quantum vacuum thrusters, then we can reach relativistic velocities with fission power... complete with all the problems that a reactionless (well, not *technically*...) drive entails...

The problem is we can't make vast quantities of antimatter, we can build a starship that doesn't require antimatter a lot more easily than we can make the antimatter, and if we build a generation ship, it is easier to make I last a long time than to make it go very fast!

Terraformer · 2014-06-14 05:19:15

Tom, you're protected from nuclear war on Luna, no need to reach for the stars...

Tom Kalbfus · 2014-06-14 08:48:31

The moon is the nearest natural object and very prominent in our skies, I'm worried about things like Nanotech and other stuff being used to destroy humanity, An interstellar spaceship might pass by unnoticed, much more so than a Moon Colony, which would basically just be an extension of Earth's civilization.

Void · 2014-06-14 09:02:25

Antius,

I enjoyed your post. There are many ways to cook an egg. Those in the UK and Europe might prefer one approach, we, and others something else.

I encourage Tom, because he tries a different method. That at the very least will expose it to testing. (As you have done).

Musk, I believe was not emerged from my local tribe, but he brings something very useful which is what I prefer to encourage.

It is interesting you and your kind seem to have this desire to take an object such as an asteroid or comet and turn it into a very long voyage spaceship. I have seen similar from your corner of the world before.

I was a Moon bug, and still am to a minor extent. I do not think we should ignore the Moon. However, having been informed of the heavy water concentrate on Mars, and the probability of Lithium salt concentrations on Mars due to its wetter past, I have upgraded my thinking about the potential for humans to settle Mars, and for Mars to become an important link in a progression towards adjacent star systems.

For Alpha-Centauri I hold out the hope for a Titan to Earth+ size world with a Nitrogen dominated atmosphere somewhere from 2.0 AU from the binary star out to the point where a Nitrogen atmosphere would collapse from the cold. That would be out to approximately Titan or a little colder.

Titan would then be the most rational playground to experiment with setting up a "Civilization" which might maintain youthful cultural capability for some time before its inhabitants degenerate into a post civilized insectoid nature.

"Specialization is for insects". Heinlein

Your idea might be modified where you find an object in an elliptical orbit and sort it's materials, and leave the "Tailings" behind, and construct a transit device from what you were going to take with you. Of course you were going to eject some of the materials for propulsion, so that's not much of a deviation.

But with that we begin to converge. Having done it that way, and then entering the new system if you could converge with a comet of that system, then you would have resupply for expansion. But this time you would modify the tailings into an impact object. Changing course to pass by the cold Nitrogen dominated world, and impacting it with the tailings, so as to elevate it's temperature temporarily. At the same time leaving behind some persons to land and take advantage of that to set up a hardened base of operations that could function in the resuming cold climate, but which would release the super greenhouse gasses that have been discussed at this site.

This could be a plan if either the Oort cloud only goes out 1 light year or merges with that of the adjacent star.

Of course the plan could also have automated probes that go ahead of it, and maybe even some small crews who arrive prior to the impact object. That might be the case if it had safe havens of some type of a natural sort.

For instance I have speculated on what would have happened to Venus if it had been ejected to the outer solar system after having had it's run-away greenhouse effect.
Likely, it would cool, and start with a CO2 ocean, and then a frozen ocean of CO2 topped with perhaps a thick Nitrogen atmosphere which would not freeze if it never cooled below 70 K at the bottom?

Then likely comets would impact and add water. Eventually the crust would be lubricated with water, and moving plates would develop like for Earth. The CO2/H20 ice layers would split at the bottoms of the "Oceans", and if the movement of the split were sufficient, then glaciation would not be able to envelop the split and something like the Mid Atlantic rift would be exposed to the atmosphere, and of course volcanism, and hot spots. Where plates dive under each other the ices would pile up and cover underground liquid pockets. With earthquakes this should be released periodically, and just perhaps produce catastrophic floods which might deliver a flow to the base of the volcanic "Mid Atlantic" zone. So, maybe even hot springs in places. So if that existed, then there might be a Oasis that would favor an early habitation of such a world with or without an impactor process.

Last edited by Void (2014-06-14 09:07:14)

Void · 2014-06-16 13:47:39

New Horizons and beyond?

Baby Steps.

http://phys.org/news/2014-06-hubble-plu … ssion.html

So there might be additional targets up to 2026, and parts of the mission continue beyond that.

http://en.wikipedia.org/wiki/New_Horizo … lt_mission

Last edited by Void (2014-06-16 13:55:05)

Antius · 2014-06-20 06:54:55

JoshNH4H wrote:

Antius, what's your take on my calculations suggesting it would be nearly impossible to get travel times down to 1500 years to another star using solar sails?

Apologies for the late reply. I havn't been able to get near my computer for about a week.

That sounds entirely reasonable. Ultimately a solar sail is fundamentally limited by the melting point of its materials and the minimum practicable thickness that it can be engineered to. If the sail is constructed from aluminium, it presumably couldn't get much closer to the sun than Mercury orbit, before it started subliming into space.

If cheap thermonuclear engines are as available in a couple of hundred years as jet engines are today, it would certainly change a lot. I think the idea of using an asteroid or comet as an interstellar vessel does have some fundamental weaknesses. Accelerating anything to high speeds is expensive, and by using a natural body we are essentially accelerating a lot of inert material. If you are spending a lot of money accelerating something, you are more likely to want useful supplies and equipment within your mass budget, than a whole lot of useless ice. None the less, I think the slow migration model of interstellar colonisation is probably the default option. In a heavily colonised solar system, it would tend to take place organically, as colonists are forced towards over more distant outer solar system bodies in order to avoid over crowding. Eventually, the point will be reached when they make the transition to a body that is not gravitationally bound to the sun.

It is interesting that some TNOs have highly eliptical orbits. Maybe these will fulfil the function of cyclers for future colonists.

JoshNH4H · 2014-06-20 13:23:25

Agreed. Interstellar transportation is so far from now that it's very hard to know what technologies will be available by the time it happens

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