Quote from: HopDavid;448336Sorry, misunderstood you.

Well since we have virtually no infrastructure in space and transportation is extremely expensive, the stuff we can't get when we're off earth is virtually everything.

Well, we can ship some stuff to the I.S.S.

Facepalms

You are determined to misread/misunderstand/misconstrue him, aren't you!

Try this: Eventually, after infrastructure has been built up, what is there that cannot be found or manufactured off Earth? Is there anything we will need and not have?

-clash

Quote from: flyingmice;448353Facepalms

You are determined to misread/misunderstand/misconstrue him, aren't you!

Try this: Eventually, after infrastructure has been built up,

Said infrastructure is accomplished with a wave of Harry Potter's wand?

Quote from: flyingmice;448353what is there that cannot be found or manufactured off Earth? Is there anything we will need and not have?

-clash

Well, given enough infrastructure, we'd have all the asteroids in the main belt converted into O'Neill cylinders and we'd be well on our way towards building a Dyson swarm. We would be lacking for nothing.

More interesting questions are what infrastructure can be built in the near term? What space resources can we use in the near term?

High transportation costs preclude a profit from mining platinum, helium 3, or what have you.

At this stage of the game, the most interesting infrastructure would be that which reduces transportation costs.

Quote from: HopDavid;448403At this stage of the game, the most interesting infrastructure would be that which reduces transportation costs.

Which would be having to set up shop at the Moon, Mars, Ceres, or a Lagrange point.

I'll try to rephrase the question yet again: Eventually, is there any resource that we would regularly need in space, that we could ultimately get nowhere but Earth, and could neither produce nor obtain in space?

This is in fact an extremely important question, because it would determine whether human survival in our solar system would be always anchored to Earth, or whether, if the Earth were cut off from space (or rendered uninhabitable or whatever) colonies elsewhere in the solar system could continue to survive, assuming they already had built the infrastructure to do so (presumably with Earth's help at first)?

RPGPundit

Quote from: RPGPundit;448519I'll try to rephrase the question yet again: Eventually, is there any resource that we would regularly need in space, that we could ultimately get nowhere but Earth, and could neither produce nor obtain in space?

This is in fact an extremely important question, because it would determine whether human survival in our solar system would be always anchored to Earth, or whether, if the Earth were cut off from space (or rendered uninhabitable or whatever) colonies elsewhere in the solar system could continue to survive, assuming they already had built the infrastructure to do so (presumably with Earth's help at first)?

RPGPundit

Just to play a bit of Devil's Advocate here, the only thing that is absolutely unique to Earth is the Earth itself. As far as resources go, having the environment of Earth kept around because it is where humanity evolved would be important to use as a baseline environment for our species, but that is the only thing I can really think of.

Depends on the technology available to us, surely.

I can conceive of technology that would let us construct any atom of our choice, given electrons, neutrons and protons as a raw material.  And of technology that would let us construct any molecule of our choice from those atoms.  And of technology that would let us create, modify or nullify gravity, radiation, force or energy fields.  

Give me that technology and I'll look you in the eye and say, "There is nothing anchoring us to Earth".  But the fact that I can conceive of that technology doesn't mean it will ever really exist.

With just the technology we have at the moment, yeah, there are plenty of things anchoring us to Earth.

Quote from: RPGPundit;448519I'll try to rephrase the question yet again: Eventually, is there any resource that we would regularly need in space, that we could ultimately get nowhere but Earth, and could neither produce nor obtain in space?

Terran lifeforms; the biodiversity of Earth could not be replicated unless the other planets were completely terraformed (and I'd question that; the lighter gravity would see species evolution differ between environments).

Even if you took a million different species of flora & fauna to a new colony, you're only getting a fraction of the Earth's biodiversity.

I'm not sure if the difference between 100 different species of ants is significant, but it's still there.

Hmm, ok, that's a good one. But how much time will it be before we can basically genetically engineer any kind of ant we want, on a per-need basis?

RPGPundit

Quote from: RPGPundit;448684Hmm, ok, that's a good one. But how much time will it be before we can basically genetically engineer any kind of ant we want, on a per-need basis?

RPGPundit

When we become like unto God.

At the point of genetically engineering life on a per-need basis, what practical difference is there between the genetic engineers and God?

Quote from: jeff37923;448687what practical difference is there between the genetic engineers and God?

The difference is a leap of faith.

Quote from: jeff37923;448687When we become like unto God.

At the point of genetically engineering life on a per-need basis, what practical difference is there between the genetic engineers and God?

There would be quite a few, none of which would really be topical to this particular thread.

RPGPundit

Quote from: Novastar;448577Terran lifeforms; the biodiversity of Earth could not be replicated unless the other planets were completely terraformed (and I'd question that; the lighter gravity would see species evolution differ between environments).

Even if you took a million different species of flora & fauna to a new colony, you're only getting a fraction of the Earth's biodiversity.

I'm not sure if the difference between 100 different species of ants is significant, but it's still there.

How much biodiversity do we need for a self sustaining eco system?

We've had a number of extinction events that wiped out many of the earth's species. But life on earth rebounded. That at leasts suggests we could have ecosystems with less biodiversity.

Quote from: RPGPundit;448519I'll try to rephrase the question yet again: Eventually, is there any resource that we would regularly need in space, that we could ultimately get nowhere but Earth, and could neither produce nor obtain in space?

This is in fact an extremely important question, because it would determine whether human survival in our solar system would be always anchored to Earth, or whether, if the Earth were cut off from space (or rendered uninhabitable or whatever) colonies elsewhere in the solar system could continue to survive, assuming they already had built the infrastructure to do so (presumably with Earth's help at first)?

RPGPundit

I don't think there is.

The biggest need is for CHON - Carbon, Hydrogen, Oxygen and Nitrogen.

These volatiles are abundant on the lunar poles, Mars and many asteroids, certainly more so as we go outward from the sun.

Energy is harder and harder to come by as we get more distant from the sun. If we don't accomplish artificial fusion power, the Kuiper Belt and Oort Cloud may remain beyond our reach.

Quote from: Novastar;448458Which would be having to set up shop at the Moon, Mars, Ceres, or a Lagrange point.

Any trips outward must first get to Low Earth Orbit (LEO). The moon and EML1's proximity to LEO make them the logical first step for transportation infrastructure.

I believe Phobos could be an important transportation hub. To make light weight elevators, it helps to have high angular velocity to lend so called centrifugal force. It also helps to have a shallow gravity well. Phobos has those. Plus a Phobos bean stalk would be deep in Mars' gravity well lending a nice Oberth benefit.



The foot of the Phobos tether pictured above is moving .6 km/sec wrt Mars' surface. Someone on Mars could reach it and match velocities with a small suborbital hop.

The stresses are small enough you don't need carbon nanotubes. You could build this tether from spun basalt which is thought to be abundant on Phobos.

Quote from: HopDavid;448862How much biodiversity do we need for a self sustaining eco system?

If Biosphere-2 taught us anything, enough so that one dominant species doesn't jeopardize the entire project (foriegn ants, trapped during construction, wiped out the various other project insects meant to enrich the soil; fortunately, the ants proved to be fairly useful in that regard, so they didn't have to scrap the project).

(Note: Biosphere-2 is not the best example, for me to use, to be honest. There's some real science in the experiment, but also a lot of junk science used to advance an agenda. Caveat Emptor.)

I'm unsure how much bio-diversity would be necessary for a sustainable bio-dome or terra-forming effort; but a robust menagerie would be better, for obvious reasons.

QuoteWe've had a number of extinction events that wiped out many of the earth's species. But life on earth rebounded. That at leasts suggests we could have ecosystems with less biodiversity.

I'll agree; but the species that evolve are likely to diverge from baseline terran lifeforms (I imagine flying insects will flourish in a low-g environment). That's really neither "good" or "bad", just different. And would take a great deal of time, unless we tampered with them intentionally (and you just have to ask an Australian how good humanity's track record has been on that).

But, for all we know, a Martian Cockroach might deficate gold.

Quote*some really brainy rocket science*

This is the part I have to leave to others. I understand the concept of delta-v, approach vectors, and the like, but the actual science of it I trust to others.
I'm an Engineer; but my empathsis is Civil, not aerospace.