Are there commerical/industrial possibilities (other than tourism) in space travel?

[BrainGlutton]

Inspired about this thread (http://boards.straightdope.com/sdmb/showthread.php?t=386376) about the proposed new Orion spacecraft -- part of a whole new family of spaceships for different purposes in NASA's Project Constellation. (http://en.wikipedia.org/wiki/Project_Constellation)

I've argued before (http://boards.straightdope.com/sdmb/showthread.php?t=262764) that the human race needs to colonize outer space -- not just explore, but colonize -- to guarantee racial survival, to free us from absolute dependence on one planet's natural ecosystem. But, of course, you can't expect people to go to space, nor to fund space travel, for that reason. Nor even because space colonization is Way Cool. Governments do it for prestige and potential military advantages and scientific research -- but none of that is going to get large numbers of people living their whole lives, and raising their children, somewhere other than Earth's surface. For that, you need some kind of economic incentive. At present, the only thing that seems to be in the offing is tourism -- short spacehops for the ultra-rich -- and, again, tourists don't go to stay. Is there anything else? Something that could make an L-5 colony or a Moon colony profitable?

Certainly there are untapped mineral resources on the Moon and every planet and moon in the Solar System. There are untapped mineral resources in Antarctica. They remain untapped because the operating costs of mining operations on a continent under a mile-thick ice shield would be too high for the enterprise to make a profit. Lunar mining no doubt would be even more expensive. And the only things we might hope to find there would be metals and stones; I doubt there are deposits of fossil fuels anywhere in the Solar System but Earth, since, as far as we know, this is the only planet that has ever had a biosphere.

SF writers often imagine a future in which we get a lot of our energy from solar power collected by orbital platforms -- but then, how would we ship or transmit the energy to Earth?

In 1966, Robert Heinlein imagined a scenario (http://en.wikipedia.org/wiki/Moon_is_a_Harsh_Mistress) where a lunar colony's economic importance to Earth would be as a farm. He failed to anticipate (1) that farming technology would improve dramatically in the coming decades and (2) that widespread industrialization would tend to slow population growth in industrialized countries. As it stands now, this planet produces quite enough food for its six billion mouths; if some are starving, that's a distribution problem. There's no apparent need to build domed or underground farms on an airless world. (By the same token, I don't expect any space colonies to be founded just for the sake of "living space.")

I've often read stories where SF writers allude to "vacuum industries" -- industrial processes that can be done optimally only in a zero-g and/or hard-vacuum environment -- but I've never been clear on what these might be.

Any other possibilities?

And, do these new NASA ships -- and new private-sector spacecraft such as Burt Rutan's SpaceShipOne (http://en.wikipedia.org/wiki/SpaceShipOne) -- change the economic calculations any?

[scotandrsn]

I see a somehwat whimsical possibility of space in the relatively near future as a retirement community, in which space is colonized first by aging baby boomers, accompanied by their caretakers and the families of those caretakers.

I suppose I get the idea from A.C. Clarke's Islands in the Sky. But as the current oldest population swell ages, an environment where gravity is not a big issue becomes quite attractive. I see LEO stations with all the conveniences, and even moon bases.

Of course much would have to be done to "tame" the space experience, but I certainly don't think it's a problem that is insurmountable within the next 20 years.

[BrainGlutton]

A space elevator (http://en.wikipedia.org/wiki/Space_elevator) would reduce the cost per kilogram of moving payload from surface to orbit -- possibly by a factor of 100 or more -- but it would be so expensive to develop and build that I can't see it happening until a large market demand is already clearly in place. Chicken-egg problem.

[BrainGlutton]

Or maybe not . . . according to this, total cost of building a space elevator according to the design of Dr. Bradley Edwards is estimated at $40 billion -- and would be expected to reduce payload costs from $20,000 to $220 per kilogram. (This does not include maintenance and operating costs.) For comparison, NASA's 2005 budget was $16 billion. The idea is not out of reach if government does it.

Why can't W make his promises about a space elevator instead of a trip to Mars?

[Squink]

Electrophoresis works better in the absence of gravity driven convection cells. There might be a commercial place for space based isotope separations (http://en.wikipedia.org/wiki/Isotope_separation).

[RickJay]

Or maybe not . . . according to this, total cost of building a space elevator according to the design of Dr. Bradley Edwards is estimated at $40 billion -- and would be expected to reduce payload costs from $20,000 to $220 per kilogram. (This does not include maintenance and operating costs.) For comparison, NASA's 2005 budget was $16 billion. The idea is not out of reach if government does it.

We had a thread debating the space elevator cost estimates.

$40 billion is, I would guess, about 25 times less than it would really cost. At least. I would be really impressed if you could build a working space elevator for a nickel less than one trillion dollars.

Why can't W make his promises about a space elevator instead of a trip to Mars?
A trip to Mars is somewhat feasible. A space elevator isn't. The technology to send human beings to Mars has been invented. The technology to build a space elevator has not. As I recall, nobody's even come up with a viable propulsion system.

[Grey]

Or maybe not . . . according to total cost of building a space elevator according to the design of Dr. Bradley Edwards is estimated at $40 billion -- and would be expected to reduce payload costs from $20,000 to $220 per kilogram. (This does not include maintenance and operating costs.) For comparison, NASA's 2005 budget was $16 billion. The idea is not out of reach if government does it.

Why can't W make his promises about a space elevator instead of a trip to Mars?Are you insane? $40 billion for a space elevator? It cost NASA about $1 billion to not successfully develop a prototype lifting body STO craft. ([url=http://en.wikipedia.org/wiki/Lockheed_Martin_X-33]X-33 (]this,[/url)). And that project was crippled mainly by the lack of success dealing with composite fuel tanks to hold the liquid hydrogen.

Until someone uses carbon nanotubes exclusively in a suspension bridge, don't even dream of dangling several hundred kilometres of the stuff from orbit.

[E-Sabbath]

A note: Who says items mined in space have to be used on Earth? Let's colonize and move out.

On the other hand, people who think they can reduce overpopulation by shipping people offplanet are not reading the current numbers right. Maybe in a hundred years, but not today.

Still, one product? Helium. Lots of it on the moon, less on earth, IIRC.

[Bryan Ekers]

A mere $40 billion? Heck, Bill Gates could set it up at Redmond as a piece of lawn furniture.

[Little Nemo]

Certainly there are untapped mineral resources on the Moon and every planet and moon in the Solar System. There are untapped mineral resources in Antarctica. They remain untapped because the operating costs of mining operations on a continent under a mile-thick ice shield would be too high for the enterprise to make a profit. Lunar mining no doubt would be even more expensive. And the only things we might hope to find there would be metals and stones; I doubt there are deposits of fossil fuels anywhere in the Solar System but Earth, since, as far as we know, this is the only planet that has ever had a biosphere.

SF writers often imagine a future in which we get a lot of our energy from solar power collected by orbital platforms -- but then, how would we ship or transmit the energy to Earth?
In many cases, we probably wouldn't. With the energy and raw materials starting out in orbit, why not move the industry up to orbit as well? You don't ship down energy and metal, you ship down finished products. Saves transportation costs and eliminates the problems of industrial waste.

[Magiver]

Are you insane? $40 billion for a space elevator? It cost NASA about $1 billion to not successfully develop a prototype lifting body STO craft. (X-33 (http://en.wikipedia.org/wiki/Lockheed_Martin_X-33)). And that project was crippled mainly by the lack of success dealing with composite fuel tanks to hold the liquid hydrogen.

Until someone uses carbon nanotubes exclusively in a suspension bridge, don't even dream of dangling several hundred kilometres of the stuff from orbit. The X-33/34 were canceled internally by NASA because they were not financially feasable. NASA never gets any credit for doing things in a cost effective manner. If you look at the cost of the 2 land rovers currently on Mars they are cheaper than the earlier attempts. Their combined cost of $500 million was 12% of the original Viking probe. They built bigger/more complex rovers in the same basic footprint.

And the shuttle never gets any credit for advancing space travel. 75% of all the astronauts who ever went into space did so by way of the Space Shuttle. Didn’t mean to hi-jack the thread but NASA gets kicked around a lot and putting 2 land rovers on Mars at the same time is worth noting.

[BrainGlutton]

Electrophoresis works better in the absence of gravity driven convection cells. There might be a commercial place for space based isotope separations (http://en.wikipedia.org/wiki/Isotope_separation).

Pardon me if I don't jump for joy on learning of a possible space-based industry that apparently produces nothing but material for nuclear weapons.

[BrainGlutton]

We had a thread debating the space elevator cost estimates.

Linky?

The technology to send human beings to Mars has been invented.

Mostly. I understand there's still the challenge of protecting the crew from the long-term effects of interplanetary radiation, which turns out to be much stronger than previously realized. See this (http://boards.straightdope.com/sdmb/showthread.php?t=379945) GQ thread.

The technology to build a space elevator has not. As I recall, nobody's even come up with a viable propulsion system.

:confused: To propel what? And what would be the requirements of such a system?

[XT]

I understand there's still the challenge of protecting the crew from the long-term effects of interplanetary radiation, which turns out to be much stronger than previously realized.

True...but there are already solutions to this problem on the drawing board. Its a matter of testing and then seeing if they are practical. Most likely our initial ventures will be by crews that aren't 100% protected...so they will be taking significant risks. Probably far less than our ancestors did when THEY explored new areas of the earth though...

To propel what? And what would be the requirements of such a system?

I would assume he meant propelling the 62+ mile elevator up and down. I'd say that compared to building the tether and the stable geo-synchronous platform for the elevator, the propulsion system will not be TOO hard to do. The Space Elevator concept though isn't ready for prime time AFAIK...we still don't have the technology even for the cables IIRC.


I'll second the Helium 3 as a possibility for commercial/industrial exploitation on the moon as a good first use. Its rare on earth but fairly plentiful on the moon. Eventually of course the sky is literally the limit. The earths resources are dwarfed by the resources available in the solar system...literally. And as E-Sabbath pointed out, there is no reason that resources gathered in space necessarily have to be shipped back to earth to be processed...eventually we will be able to move many of our industries into space so that perhaps only fully manufactured goods or parts need to shipped down (and of course, shipping stuff down is a lot easier than bringing it up into space), while the majority of our space based needs are made on the spot, so to speak, without having to fight our gravity well to get em up there. Everything thats needed is out there...including the MOST valuable resource of all. Water.

-XT

[CalMeacham]

Not only Clarke and Heinlein, but John Campbell addressed the issue of space industries. IIRC, his essay is the last piece (and the only non-fiction piece) in the collection The Best of John Campbell.

As I've read from him and from other sources, some of the advantages are:

1.) A far better vacuum than we can maintain on earth

2.) Microgravity, which is useful in a number of circumstances, such as creating items with no gradients due to gravity and convection, to growing strain-free crystals, etc.

3.) Mining and manufacture for items intended to be used in orbit or elsewhere off the earth.

4.) Support for items that need to be in orbit (communications satellites, GPS, weather satellites, power satellites)

5.) Atmosphere-free astronomy (not a paying industry, admittedly, except for some photo and tourist value)

6.) Access to plenty of hard UV, cosmic rays, and the like. There are actually situations in which you want to have hard radiation bombard something.

[BrainGlutton]

A note: Who says items mined in space have to be used on Earth? Let's colonize and move out.

Eventually, but in the early stages, until space colonies become more or less self-sustaining, they would have to be justified in terms of financial returns to Earthbound corporations and/or governments, which means producing things for Earth's markets. Colonizing space will not be like colonizing the Americas was. Settlers can't just grab a piece of land and start farming and forget the mother country exists.

Still, one product? Helium. Lots of it on the moon, less on earth, IIRC.

But what's it good for? (Assuming we never crack the controlled-fusion nut.)

[BrainGlutton]

6.) Access to plenty of hard UV, cosmic rays, and the like. There are actually situations in which you want to have hard radiation bombard something.

:confused: Such as?

[XT]

Eventually, but in the early stages, until space colonies become more or less self-sustaining, they would have to be justified in terms of financial returns to Earthbound corporations and/or governments, which means producing things for Earth's markets. Colonizing space will not be like colonizing the Americas was. Settlers can't just grab a piece of land and start farming and forget the mother country exists.

Yep. Sort of like the initial colonies of the Euro's in the new world, ehe? The initial start up costs for those were pretty significant too...and the dangers were epic, both getting there and then surviving. Note the numbers who DIDN'T survive.

Eventually though such colonies could very well be self sufficient...in fact, they could be quite profitable, especially with heavy automation. After all, their pool of potential resources, once outside the Earth gravity well, is a lot more than our potential pool stuck on this ball of mud.

-XT

[CalMeacham]

Such as?


1.)Intentionally creating defects in crystals (this is what I used it for in grad school)

2.) Curing of polymer coatings and paints

3.) Cross-linking of polymers

4.) Surface treatments for materials (UV causes desired chemical change in outer layer)

[XT]

But what's it good for? (Assuming we never crack the controlled-fusion nut.)

Well, thats a pretty big assumption. Even assuming that though, its useful in research for fusion, and valuable for that alone (be a hell of a lot MORE valuable though if we figure it out).

Here are some links...sorry for the drive by links, I am between meetings:

Wired (http://www.wired.com/wired/archive/8.08/helium.html)

Use for anti-corrosive and cryogenics (http://www.corrosionsource.com/handbook/periodic/2.htm)

ABC (http://www.abc.net.au/news/newsitems/200411/s1252715.htm)



Wiki (http://en.wikipedia.org/wiki/Helium-3)

-XT

[Chronos]

The Space Elevator concept though isn't ready for prime time AFAIK...we still don't have the technology even for the cables IIRC.Really, the cable is the only significant thing we don't have yet. There are other problems, too, of course, but once we have the material for the cable, everything else will quickly fall into place. And the great thing about the cable is that carbon nanofiber would be an incredibly useful material for many purposes, on Earth and in space. Even if nobody's trying for a space elevator, they'll still work on producing nanofiber for suspension bridges and skyscrapers (and fishing lines and golf clubs, of course).

At the moment, the only direct commercial values in space flight are satellites, which can provide a variety of commercial (and non-commercial) benefits. Zero-g crystallography gets a lot of hype, but for now, it's mostly just hype. But if we really got an industrial presence up and running in space, there's a lot we could do. A space elevator or other cheap launch system would help a lot, of course, but even without cheap launches, I could envision asteroid mining, for instance, being profitable in the long term. Once the infrastructure is in place, you could keep it all in orbit, and just bring an asteroid on a controlled re-entry every so often, for a cheap supply of iron, nickel, and other metals. Remember, no matter how expensive it is to get things up there, it's almost free to get them down.

[BrainGlutton]

Remember, no matter how expensive it is to get things up there, it's almost free to get them down.

As RAH well knew. (http://en.wikipedia.org/wiki/Moon_is_a_Harsh_Mistress) ;)

Which raises another point: There was a time when we might have hoped commercial exploitation in space could be piggybacked on military space travel -- who controls the sky controls the surface, and if the military program included manned orbital platforms, they might need a lot of independent contractors for entertainment, just to start with . . .

But the Cold War is over, and our perceived enemies of the moment are not likely to have any space-travel capacity in our lifetimes.

[Tastes of Chocolate]

I've often read stories where SF writers allude to "vacuum industries" -- industrial processes that can be done optimally only in a zero-g and/or hard-vacuum environment -- but I've never been clear on what these might be.

Any other possibilities?

Per a NASA paper,
here (http://history.nasa.gov/SP-401/ch16.htm), bottom paragraph, "the electrolytic growth of powders for catalyst applications."

Actually, Space Island Group (http://www.spaceislandgroup.com/manufacturing.html) has a bunch of ideas. New/stronger alloys, semiconductors, pharmaceuticals (more pure)...

[Sam Stone]

Or maybe not . . . according to total cost of building a space elevator according to the design of Dr. Bradley Edwards is estimated at $40 billion -- and would be expected to reduce payload costs from $20,000 to $220 per kilogram. (This does not include maintenance and operating costs.) For comparison, NASA's 2005 budget was $16 billion. The idea is not out of reach if government does it.

Why can't W make his promises about a space elevator instead of a trip to Mars?

[url=http://news.com.com/NASA+hosting+space+elevator+competition/2100-11397_3-5907569.html]NASA Hosting Space Elevator Competition (]this,[/url)

The "Beam Power Challenge," which will kick off Saturday at 5 a.m. PST, will test the design and efficiency of robot climbers, machines that can ascend and descend a 50-meter tether ribbon while carrying a payload.

Seven teams from the United States and Canada will get three chances to climb the ribbon, having to travel at a minimum speed of 1 meter per second. For each climb, teams get a score that's a product of their payload mass and average velocity. The team with the highest score will win $50,000.

...

The "Tether Challenge" is designed to help foster the development of strong but lightweight materials that could support the space elevator. The contest requires teams to develop a tether that can improve on a commercially available one by 50 percent in breaking force. Teams will compete in a "pull-off," where each pulls against the other until one breaks, to find the lightest and strongest. Finally, the best-performing tether will compete against the "house" tether, or off-the-shelf material, and if successful, will win the $50,000.

Most people believe that the space elevator will be made of carbon nanotubes, but that technology is still in early development.

"We're trying to use prizes to encourage development of that technology," one project contractor for NASA said.


Small potatoes, but at least NASA is showing an interest.

[XT]

Plus there is always the null-G sex industry. Blind folded pin the tail on the, er...well, whatever you want to pin the tail on I guess. Could be big (*cough cough*)!

:p

-XT

[Squink]

But the Cold War is over, and our perceived enemies of the moment are not likely to have any space-travel capacity in our lifetimes.Surely you're not suggesting that Iran might not 'bust a nuke' above the atmosphere and blow our space assets to hell with EMP?

Report of the Commission to Assess United States National Security Space Management and Organization (http://www.defenselink.mil/pubs/space20010111.html)

From which: Rumsfeld Commission Warns Against "Space Pearl Harbor" (http://www.spacedaily.com/news/bmdo-01b.html)

Those are back in 2001. Here's some current thoughts on the subject:
Ten Propositions Regarding Space Power
The Dawn of a Space Force (http://www.airpower.maxwell.af.mil/airchronicles/apj/apj06/sum06/harter.html)

We very well may have a large contingent of space-hookers, or 'independent contractors' as you call them, by 2025.

[BrainGlutton]

Plus there is always the null-G sex industry. Blind folded pin the tail on the, er...well, whatever you want to pin the tail on I guess. Could be big (*cough cough*)!

:p

-XT

I recall a filksong -- "A Reconsideration of Anatomical Docking Maneuvers in a Zero-Gravity Environment," by Diana Gallagher -- about the [*ahem*] technical challenges. Solutions suggested included:

Together tethers would prevent a random wandering
Magnetic harnesses incorporating alternating poles . . .

Can't find the complete lyrics online, but I did find the lyrics to this (http://www.songworm.com/lyrics/songworm-parody/MakingLoveWeighingNothingA.html) one.

[BrainGlutton]

On the same topic, see here. (http://cosmiclog.msnbc.msn.com/archive/2006/07/28/1507.aspx)

[RickJay]

:confused: To propel what? And what would be the requirements of such a system?
You're kidding, surely? Whaddya gonna do, climb up the rope?

We're not talking about a 62-mile climb; it's a 62,000 mile climb. You do need some sort of engine to get you up there, and unless you want it to be a remarkably long trip, it has to be reasonably fast.

It's simply a project of staggering potential cost that would require the commitment of a fairly noticeable fraction of the world's resources. Christ, the space station alone that holds the other end of the tether could cost a trillion dollars. The insanity of a $40 billion price tag can be quickly illustrated by pointing out that the International Space Station, which is about one hundredth as technologically challenging and complicated to build, cost at least $30 billion.

[BrainGlutton]

We very well may have a large contingent of space-hookers, or 'independent contractors' as you call them, by 2025.

I hope against hope the emergent slang term will be "sky hookers"! :)

[BrainGlutton]

Surely you're not suggesting that Iran might not 'bust a nuke' above the atmosphere and blow our space assets to hell with EMP?

I was thinking of al-Qaeda, the Taliban, etc. -- guys who couldn't tell a spaceship from a portrait of the Prophet. As for Iran, even if they ever do develop a nuke, do they have the capacity to get it out of the atmosphere?

[BrainGlutton]

You're kidding, surely? Whaddya gonna do, climb up the rope?

We're not talking about a 62-mile climb; it's a 62,000 mile climb. You do need some sort of engine to get you up there, and unless you want it to be a remarkably long trip, it has to be reasonably fast.

Various approaches to that are being considered. See here. (http://en.wikipedia.org/wiki/Space_elevator#Climbers)

[Squink]

As for Iran, even if they ever do develop a nuke, do they have the capacity to get it out of the atmosphere? The Shahab-3 (http://www.globalsecurity.org/wmd/world/iran/shahab-3.htm) should manage.

[FRDE]

You're kidding, surely? Whaddya gonna do, climb up the rope?

We're not talking about a 62-mile climb; it's a 62,000 mile climb. You do need some sort of engine to get you up there, and unless you want it to be a remarkably long trip, it has to be reasonably fast.

It's simply a project of staggering potential cost that would require the commitment of a fairly noticeable fraction of the world's resources. Christ, the space station alone that holds the other end of the tether could cost a trillion dollars. The insanity of a $40 billion price tag can be quickly illustrated by pointing out that the International Space Station, which is about one hundredth as technologically challenging and complicated to build, cost at least $30 billion.

Arthur C Clarke wrote a SF novel around a space elevator.

It might be there that I picked up the idea that a long cable actually pulls itself up, something to do with negative centripetal force. There is also the way a yoyo works.

If we had the fibre technology, then the rest of the task could be comparatively low tech - a sort of bootstrap operation.

[CalMeacham]

Arthur C Clarke wrote a SF novel around a space elevator.



Lotsa people have, by now. Clarke's Fountains of Paradise came out back in 1982 or so, at almost exactly the same time as Stanley Schmidt's The Web Between the Worlds, to which Clarke wrote the introduction. He pointed out the incredible similarities, which he attributed mainly to the fact that they were both extrapolating from the same background. In Clarke's story the fibers are defect-free carbon. In Schmidt, defect-free silicon. Both novels have "climbers" for the space elevators named "Spider"

[Typo Knig]

Lotsa people have, by now. Clarke's Fountains of Paradise came out back in 1982 or so, at almost exactly the same time as Stanley Schmidt's The Web Between the Worlds, to which Clarke wrote the introduction. ...

Nitpick: Charles Sheffield wrote The Web Between Worlds (http://www.amazon.com/-Web-Between-Worlds/dp/0671319736/sr=1-1/qid=1157559051/ref=sr_1_1/103-5229548-4827859?ie=UTF8&s=books), not Stanley Schmidt.

The two books are a Lovely "Time to Railroad" coincidence, though!

Now what I came to pick on:

As I've read from him and from other sources, some of the advantages are:

1.) A far better vacuum than we can maintain on earth

...


Nope, sorry, that's wrong. Nearly as common a misconception as NASA inventing Tang (http://en.wikipedia.org/wiki/Tang_%28drink%29) (a "spin-off"), rather than just buying a bunch ("spin-in").

From Wikipedia's page on High vacuum (http://en.wikipedia.org/wiki/High_vacuum)

In Low Earth Orbit (about 300 km altitude) the atmospheric density is about 100 nPa, (10^-9 Torr,) still sufficient to produce significant drag on satellites.Most artificial satellites operate in this region, and they need to fire their engines every few days to maintain orbit.

Beyond planetary atmospheres, the pressure from photons and other particles from the sun become significant. Spacecraft can be buffeted by solar winds, but planets are too massive to be affected.

On the same Wiki page, they compare pressure ranges of Outer Space to various "grades" of vacuum. Outer space ranges from merely "High" to "Extremely High" Vacuum. "High" vacuum is easily achieved in an undergraduate laboratory. If you keep things clean, you can approach Ultra High Vacuum in an undergraduate setting.

I worked with Ultra-High Vacuum (http://en.wikipedia.org/wiki/Ultra_high_vacuum) systems for a time (better than High vacuum, not as good as Extremely High vacuum). What you want from a vacuum system is a controlled, extremely clean environment. Just "opening up the window" on a spacecraft will NOT do. Spacecraft outgass all kinds of miscellany. If you want an atomically clean surface you don't want crap outgassing on it. At 10^-6 torr (middle of the "high vacuum" range), a single layer (http://en.wikipedia.org/wiki/Monolayer) of contaminants forms on a surface in about a second. At 10^-9 torr (UHV), that would be about 1,000 seconds = 17 minutes. Doesn't give you a lot of time for surface processing or analysis.

UHV systems are not terribly cheap, since they require stainless steel construction, high-quality welds, multiple pumps, and scrupulous cleaning. But they are much cheaper than anything in orbit.

That's the big hang-up with space industries, IMNSHO. It is prohibitively expensive to put stuff in space. Bob Park, skeptic extrordinaire, said that if we filled the space shuttle with coal dust at launch, and - just by it going into orbit - it returned full of diamonds, that would still not pay for the cost of the shuttle mission. I have no cite, and I have not run the numbers myself, so he could be wrong. But I am confident he's closer to being right than space advocates would like.

[CalMeacham]

Typo -- Having worked with vacuum systems myself, I gotta say that the advantages of a huge, almost maintenance-free vacuum system speak for themselves. I'd no more just stick my vacuum thing outside an outgassing spaceship that put it near a plastic window in a vacuum on earth. But in a low-outgassing box in space I'd have a low-vacuum area that wouldn't require a series of pump or cold traps. Heck, put it on the dark side of something and you have a built-in cold trap. If you already have you stuff in space, having mined it there, you have a good incentive for using space as your vacuum.

[Saltire]

The cutting edge of Space Elevator optimism is here in Washington State. LiftPort Group (http://www.liftport.com) is aiming at having the thing done by 2018 for roughly 6-10 billion dollars US. I'm wishing them well.

They say their progress in developing the tech to form the ribbon is actually a little ahead of the schedule they expected to achieve, but the power-beaming tech they'll need to power the lifters is a bit behind.

[BrainGlutton]

They say their progress in developing the tech to form the ribbon is actually a little ahead of the schedule they expected to achieve, but the power-beaming tech they'll need to power the lifters is a bit behind.

Why is "power-beaming" necessary? Why not use (non-load-bearing) power cables, strung along the main elevator cable?

[RickJay]

Why is "power-beaming" necessary? Why not use (non-load-bearing) power cables, strung along the main elevator cable?
A 62,000 mile long power cable? You'd lose a massive amount of power along the way; that's orders of magnitude longer than any power line used today. How're you going to reduce power loss?

[Saltire]

Why is "power-beaming" necessary? Why not use (non-load-bearing) power cables, strung along the main elevator cable?Two things I can think of right off.

1)It would add a phenomenal amount of mass to the ribbon (remember, this is a cable about 100 megameters (100,000km) long), which would almost surely make it too heavy to hold itself up. In the ribbon of the elevator, there's really no such thing as non-load-bearing--either you hold up your own weight, or something else has to be made bigger to hold you up.
2)Unless you work out a way to make the cable superconduct, there would be a lot of loss over 100 megameters. No ground-based power cable is even close to that long, and they have huge losses. Near the top of the elevator, there'd be no power left to tap. [Technically, you only need power up to the Clarke orbit. After that, the lifter would fall away from Earth naturally. But I think it would still need power to brake, otherwise it would hit the counterweight at high speed.]

Another common suggestion is to include a lot of batteries or some sort of reactor on the lifter to power the lift. If you do that, you get the same problem rockets have: for every kilo of payload, you have to ship along kilos of power-stuff, be it hydrogen-oxygen fuel, fissile material or batteries. You end up not being a cheaper way to orbit. Beaming the power from the ground allows you to be almost all payload.

[iamthewalrus(:3=]

Another common suggestion is to include a lot of batteries or some sort of reactor on the lifter to power the lift. If you do that, you get the same problem rockets have: for every kilo of payload, you have to ship along kilos of power-stuff, be it hydrogen-oxygen fuel, fissile material or batteries. You end up not being a cheaper way to orbit. Beaming the power from the ground allows you to be almost all payload.It's not nearly as bad as a rocket, though. You don't have to carry reaction mass. Crawling is a far more efficient use of power than rocketry. I don't know the exact numbers, but I'd guess that it's several orders of magnitude more efficient.

[BrainGlutton]

The cutting edge of Space Elevator optimism is here in Washington State. LiftPort Group (http://www.liftport.com) is aiming at having the thing done by 2018 for roughly 6-10 billion dollars US. I'm wishing them well.

From their site:

The elevator will be anchored to a specially designed ocean going vessel named, "The LiftPort" near the equator in the Pacific Ocean, and to a small man-made counterweight in space

Hmmm . . . Why at sea? (Is it just because the U.S. has no territory on the Equator?)

[Stranger On A Train]

A few thoughts:

While the idea of invaluable space industries and the unique products they could produce in microgravity sounds good in theory, the actual transportation costs, skilled labor, overhead of maintaining a habitable environment, and capital investment in developing the technology make it prohibitive from a cost-benefits standpoint. Even if you can make, say, some kind of super-strong crystal-fiber matrix composite that replaces normal structural materials, the cost is going to be so high that it won't be useful in any but the most exotic applications. Think of it as the difference between a commodity x86-based desktop machine versus a high-end SGI Origin server; the SGI is (or rather, was) clearly the better hardware for doing certain types of operations (graphics rendering and visualization), but the PC was so cheap and demonstrated profit margins based on economies of scale that development of it outpaced that of the MIPS processor...and now your typical renderfarm is a few hundred x86 or Opteron boxes using MPI, and SGI is in recievership. The only space-based industry to date to show a healthy profit is the telecommunications industry, and that only because of heavy government investment into the underlying launch, networking, and computing technology combined with a pre-evident manyfold expansion in bandwidth demands. It's possible that some expansive, insatiable demand could develop for zero-gee pharmaceuticals or exotic high strength materials, but it would require both foresight and heavy, long-term investment to make this the driving force in developing commerical space industry.

There are, of course, an enormous wealth of metals available for the taking; a small, mineral-rich NEO likely has a greater mass of industrial metals than we could hope to extract from any single flatland mine, and without serious complaints about strip mining or environmental hazards. (There'll no doubt be a few well-intended flakes who want to protect an asteroid from exploitation, but without a spotted owl or baby seal in sight it'll be tough to garner public opinion.) However, aside from the costs, again, of getting their and paying your labor force, it's not likely to be a great investment vis a vis Earth-mined commodities. We don't have any serious lack of structural or common metals like iron, aluminum, copper, tin, lead, magnesium, nickel, et cetera to the extent that a new massive supply would be competitive, and dumping a glut of rare earths and exotic metals like tungsten, tantalum, iridium, rhenium with make up such a small (if significant) part of the market would result in large price reductions assuming that someone doesn't come up with new demands for these metals; even if they do, the new markets would have to maintain high enough margins to justify the decades of investment required to get to the point of exploiting these resources. What private, profit-motivated organization is going to take that risk?

The real reason to develop space industry and mine asteroids is because it is too expensive to haul stuff up from the Earth's surface; permanent human habitats in space will have to become self-sufficient, space elevators, catapults, or any other cheap transport aside. It just costs too damn much, in terms of energy, to pull against gravity, and it makes no sense to ignore the big chunk of nickel-iron floating a few thousand kilometers away. But first you have to justify the costs of establishing human presence, and not in terms of value to itself. That's a hard slog; talking about the hypothetical future of humanity, the drive to explore, spreading your eggs around, and so forth sounds visionary (and makes for some pretty good cinema on occasion) but it doesn't incline most people to spend more than the price of a movie ticket. A few hundred billion dollars, in the context of developing vast new resources, gaining both abstract and applied knowledge, protecting Earth from catastrophic extraterrestrial threats, et cetera is a pittance. But come budget time at Congress, it's an easy line item to cut out in favor of supporting the latest politically lucurative issue or holding a press conference about assigning your latest Golden Fleece award.

As for the space elevator; where there's a will, there's a way. People who claim that all the technical issues have been resolved, and that it's merely a matter of basic civil engineering are living in a fantasy where undeveloped high strength materials can be cranked out in necessary and flawless form like knitting yarn and orbital hazards are minor irritations. On the other hand, naysayers who insist that it can never happen (or will be so absurdly expensive that it couldn't even be considered) ignore the history of technological development from the wheel and axle through commerical air travel and high speed computing which was always ripe with pundits espousing the impossibility (either physical or fiscal) while the metaphorical ground was falling out from under their feet.

We're not even close to being able to erect and operate such a thing today, and to try to do so might well exceed the trillion dollar estimate previously thrown out. But as the technology develops (preferably, guided and supported by parties interested in making it a reality as fast as development allows) and becomes both physically and economically feasible, the concept will go from being an impossibility to a mere engineering nightmare--just like every major, ground-breaking monument to the desire of mankind to do it bigger, better, faster, cheaper, and most importantly, with a big celebratory ground-breaking and giant Jumbotron screens advertising the latest in sweat-shop sports attire. It's not going to happen in ten years or twenty, but if the next century rolls around with nary a serious effort in sight, I'll be awfully surprised. I wouldn't be surprise, though, to learn that the official language of the beanstalk is Manderin, Hindi, Malay, or Korean. (I have hopes that English will remain the lingua franca, 'cause I don't think I'm up to learning an Oriental language after I pass triple digits, but maybe they'll have a pill or something for it by then.)

Besides, one trillion dollars in the scale of (hopefully) millenia of human development and technical evolution? A drop in the bucket, a mere charged electron in a stream of plasma emanating from a solar flare, a fleeting trifle of opportunity cost well-spent. Ferdinand and Isabella pissing and moaning about the cost of three ships and ninety men for a fortune that built and funded an empire (albeit, one predicated upon suppressing the natives and ultimately squandered on excess). If it only costs one trillion, it'll be worth its impulse in angular momentum many times over.

Stranger

[FRDE]

This space lift thing has got me thinking

If one managed to produce a single filament that supported its own weight plus, say a small percentage for the payload, then one could equally well extrude a tube of the stuff, since each fibre is supporting its own weight.

At that point one could simply shift the payload on a column of hot :-} air, possibly assisted by suction vents at various altitudes, using wind. The whole thing could be a bit like a Pater Noster lift using air instead of steel cables (or whatever those things use).

A great way of 'selling' the project would be to present it as a Carbon storage mechanism.

[Der Trihs]

But I think it would still need power to brake, otherwise it would hit the counterweight at high speed.Nope; since it's losing energy, by slowing, you can use the deceleration process as a generator and gain power. Same principle as sticking a waterwheel in a waterfall, using a "falling" cargo pod instead of falling water.

As long as the mass going up and down is balanced, the only net energy loss should be due to the inefficiencies of the mechanisms involved. The pods going down can power the ones going up. You'll still need a generator or battery of course, since the travel load is unlikely to be perfectly balanced, but it might even be a net gain if more is going down than up.

[Nava]

Pardon me if I don't jump for joy on learning of a possible space-based industry that apparently produces nothing but material for nuclear weapons.

And radiology, biochemistry studies...

Isotopes are used in quite a lot of medical applications, mostly covered by the two large umbrellas I mentioned above. Other chemical pathways are also studied using isotope markers, but the "bio" label helps attract grant-givers' interest for some reason ;)

[Cervaise]

Hmmm . . . Why at sea? (Is it just because the U.S. has no territory on the Equator?)Partly that, but also partly as a hedge against something going wrong. It seems better, intuitively, to drop a payload into the ocean than on land, especially as it's likely a city will spring up around the elevator's base.

Of course, this neglects three points: First, if the anchor point is really that significant a nexus for commerce and other activity, then a floating city will evolve, Snow Crash style, negating that part of the rationale; second, as water is not compressible, dropping a huge object into the ocean will produce a pretty significant and probably destructive wave event which will affect people thousands of miles away; and third, if something really goes wrong with the elevator, it doesn't matter where the anchor point is (see Red Mars).

[BrainGlutton]

So far in this thread we've had serious arguments for (or at least suggestions of) the technical and/or commercial viability of:

1. Low-g or zero-g retirement communities in space.

2. Live hands-on support for communications satellites, weather satellites, GPS satellites, etc. (consider that these things have been functioning well enough without such support up to now).

3. Atmosphere-free astronomy (of course, the Hubble telescope already exists).

4. Mining the mineral resources of extraterrestrial planets, moons and asteroids. E.g., mining the Moon for helium-3 (potentially nuclear-fusion fuel, if controlled fusion is ever achieved; not clear what else it might be good for).

5. Relocating some industrial production to orbit, reducing industrial pollution of Earth's ecosystem; use space-derived raw materials, ship only the finished products to Earth.

6. Manufacturing in a natural hard-radiation environment -- some industrial applications for that, including intentionally creating defects in crystals, curing of polymer coatings and paints, cross-linking of polymers, surface treatments for materials.

7. Manufacturing in a natural microgravity environment -- various industrial applications, including separations of isotopes by electrophoresis (products useful for nuclear explosives, also for radiology and other medical applications), growth of perfect crystals, manufacture of metal alloys, semiconductors, pharmaceuticals.

8. Manufacturing in a natural near-vacuum environment -- but there's some dispute over how hard-vac the environment actually is or can be made, and I'm still not clear on what use that is for industrial purposes anyway.

(The potential of a "null-g sex industry" was mentioned; sadly, that must be discounted as essentially a form of tourism; remember, we're talking about things that will take humans into space to stay.)

One thing hasn't been seriously addressed yet: Solar power satellites. (http://en.wikipedia.org/wiki/Solar_Power_Satellite) Is this viable or not? And how would the power be shipped/transmitted to Earth? Microwave beaming seems to have a lot of potential for environmental hazards.

[Stranger On A Train]

One thing hasn't been seriously addressed yet: Solar power satellites. (http://en.wikipedia.org/wiki/Solar_Power_Satellite) Is this viable or not? And how would the power be shipped/transmitted to Earth? Microwave beaming seems to have a lot of potential for environmental hazards.It's hard to say whether solar power satellites are technically viable; it's almost certain, given a linear progression of today's technology, that they are fiscally and logistically uncompetitive.

A single geostationary satellite would be a massive structure, requiring many launches plus orbital construction. The former isn't terribly prohibitive if we assume that progression of competitive commerical launch vehicles and economies of scale--for a launch system that runs $200/kg you can assume a few hundred million in launch costs--but the assembly costs (assuming they require human labor rather than some kind of automated system) are going to be enormous, in the tens of billions of dollars. There are also maintanence and replacement costs; orbital space is a hostile environment, and regular repair (presumably by humans, or at least human-operated remote-control devices) will be required. This is possibly within reach of a government-funded organization like NASA or the ESA, but probably outside of what a commercial enterprise would undertake.

The structure, being in GSO/GEO (30-50km) is going to run right through the heart of the outer Van Allen radiation belts. This is dealt with on communication satellites by shutting down or isolating systems to help protect them, but I don't think that would be an effective strategy for a massive solar power satellite. You could give the satellite an elliptical geosynchonous or even a periodic synchronous orbit to avoid the worst of the Belt, but then you are reducing power transmission efficiencies (beaming throgh a thicker part of the atmosphere or having "dark" periods where no receiver is in sight).

For a satellite in circular GEO orbit, your collector has to be near the equator, else you're beaming through a substantially thicker atmospheric layer. This means that you then have to transfer the energy from your equatorial receiver to areas where it is demanded, which are predominantly North America and Europe. This will run into problems with line losses and throughput of the conventional electricty transmission grid (http://en.wikipedia.org/wiki/Electric_power_transmission). If you put it in SGO or a periodic orbit with a high apogee dwell time as described as above, you could place receivers at higher latitudes and collect energy for a significant amount of the orbital period, but you'll still lose a majority of operational time. Multiple receivers spread around the globe could help with this, but then you'll have to find the real estate (tens or hundreds of square kilometers) in different locations to allow for this. Mobile marine receivers could be used, but again you have the problem of transmission or storage of incoming energy.

The technology of beaming massive microwave energy (presumably in the terawatt range) is untested, both from feasibility and environmental impact. Advocates claim that the beam will be sufficiently unconcentrated to not do harm to a bird or aircraft that wanders into the beam, and other schemes have been proposed to ensure that leakage is prevented by use of a targeted focusing mechanism, but that's all just theory for now. There are sufficient unknowns to make it difficult to predict what the actual problems and costs will be.

Compared to ground-based solar power facilities (about which the costs and problems can be reliably estimated) solar power satellites just aren't in and of themselves a compelling argument. (Gerald O'Neill argued the case for them, but more as a justification for building the eponymous habitats, and then on a scale that is only feasible given an existing large scale space mining and construction industry.) It might be possible if you already have the infrastructure in place and the technology developed, but arguing for financing the development based upon speculation of their effectiveness is a hard point to justify. Like most speculative technologies, it's a chicken-and-egg problem: if you have the technology, you'll reap the rewards, but only if you have capital to develop the technology. For the most part, the only time we've been able to overcome an inertial resistance to funding such development is in response to political impetus; the "ultimate weapon" to win a globe-encompassing war, a race to be the first in some new field of human achievement, et cetera.

Stranger

[BrainGlutton]

The structure, being in GSO/GEO (30-50km) is going to run right through the heart of the outer Van Allen radiation belts. This is dealt with on communication satellites by shutting down or isolating systems to help protect them, but I don't think that would be an effective strategy for a massive solar power satellite. You could give the satellite an elliptical geosynchonous or even a periodic synchronous orbit to avoid the worst of the Belt, but then you are reducing power transmission efficiencies (beaming throgh a thicker part of the atmosphere or having "dark" periods where no receiver is in sight).

Hmmm . . . I don't suppose there's any way to use the Van Allen Belts (http://en.wikipedia.org/wiki/Van_Allen_Radiation_Belt) themselves to generate power?

[Stranger On A Train]

Hmmm . . . I don't suppose there's any way to use the Van Allen Belts (http://en.wikipedia.org/wiki/Van_Allen_Radiation_Belt) themselves to generate power?Possibly. Robert Forward came up with the HiVolt (http://en.wikipedia.org/wiki/HiVolt) concept to deplete the belts (to reduce the radiation hazard; if you can create or connect to a sink of reduced charge, you could presumably generate a current from the resultant potential. On a more general note, the ionosphere has a much higher concentration of charged particles than ground; an Earth-to-orbit tether could potentially create a potential difference that could be exploited. Whether either of these schemes are viable and cost-effective is another question. "Free energy" is only free insofar as it is available to be exploited; from a certain point of view, coal and oil are "free" save that you have to dig it up, refine/process it, and combust it. (Of course, solar, wind, and hydro don't produce the kind of byproducts that fossil fuels do, and don't create the radiation hazard of nuclear fission or D-T fusion.)

Thinking about the solar power satellite thing a bit more, there might be better ways to scale or distribute the cost, and better protect the overall system. Instead of building a massive, monolithic power generating array with a transmitter in GEO, you could instead build fleets of individual satellites or small arrays in a variety of better protected orbits, which would then beam power by laser or microwave to a single or small series of orbit-to-Earth transmitters. Even if you want to cluster your solar collecters, they don't need to be rigidly connected together, if at all; you could tether them, using tidal forces to keep them tensioned and oriented, or let them orbit free and use small ion-dust rocket motors (drawing energy from excess solar power generation or during times when the satellite can't connect to a transmitter) to maintain or move to an optimum orbit. You'd still have to validate the transmission from orbit to ground station concept, but you could at least select better orbits and distribute your overall system to limit environmental damage and hazard.

Depending on the cost of launching and deploying individual elements, you might not even need a human maintenance presence, which is likely to be the largest expense; you'd just replace as necessary, similar to communications satellites. Of course, that negates the justification for human exploration as a de facto requirement of the system, but reliable and inexpensive boost to orbit capability is the sine qua non of space exploration; once you have that, the costs of getting elsewhere become marginal rather than overwhelming, even with low Isp chemical propulsion. (You still have technological hurdles to overcome, like radiation shielding and the effects of microgravity, but once mass doesn't become a critical factor in your costs, you can expand your options.)

In the end, I don't think you can justify human space transportation in terms of profit on Earth; it has to be justified in terms of itself, i.e. the benefit is that contributes to the ability to travel further and explore more. In many ways, human exploration just isn't, and probably never will be, cost-effective, owing to the risk to and delicacy of human beings with respect to unmanned probes. The arguments otherwise generally come off, if well-intentioned, as specious and/or ill-informed. We should go there because it is interesting and unexplored, not because doing so will give us high-strength materials and exotic drugs.

Stranger

[BrainGlutton]

We should go there because it is interesting and unexplored . . .

And so that we can be sure the human race can survive another ten billion years. That's the most important reason.

[Squink]

Possibly. Robert Forward came up with the HiVolt (http://en.wikipedia.org/wiki/HiVolt) concept to deplete the belts...There's also this DARPA belt depletion plan (http://www.physicsweb.org/articles/news/10/8/16/1):
A nuclear detonation releases vast numbers of electrons that would "pump up" the Van Allen belts, which are two bands of charged particles trapped high in the atmosphere by the Earth’s magnetic field. As these intense streams of belt electrons hit the satellites, they produce penetrating X-rays causing significant damage to onboard electronics and corrupting data sensors.

To mitigate this effect, the US Air Force and the US Defense Advanced Research Projects Agency have proposed a remediation system that uses radio waves at very low frequencies of about 20 kHz to flush the excess energetic particles from the belts and dump them into the upper atmosphere, well away from the satellites.

[RickJay]

And so that we can be sure the human race can survive another ten billion years. That's the most important reason.
"Another"?

It strikes me as being more than a little silly that we should be worried about the species surviving longer than the Sun can support life on Earth. No multicellular species on Earth has more than the tiniest fraction of that length of history under its belt. Our descendants in a billion years will likely no longer be Homo sapiens. And to be perfectly honest I really don't give a crap how they're going to be doing. I'm concerned about my daughter and her children and maybe their children but how people are doing 1,000,000,000 years from now isn't worth a nickel to me.

[BrainGlutton]

It strikes me as being more than a little silly that we should be worried about the species surviving longer than the Sun can support life on Earth. No multicellular species on Earth has more than the tiniest fraction of that length of history under its belt. Our descendants in a billion years will likely no longer be Homo sapiens.

That doesn't matter. What matters is that they will be our descendants, that we won't be an evolutionary dead end.

And to be perfectly honest I really don't give a crap how they're going to be doing. I'm concerned about my daughter and her children and maybe their children but how people are doing 1,000,000,000 years from now isn't worth a nickel to me.

So far as we know, there is only one living species in the Universe that has the mental capacity to appreciate its beauty and wonder. Shouldn't preserving its existence by a high priority?

[Laughing Lagomorph]

...
Actually, Space Island Group (http://www.spaceislandgroup.com/manufacturing.html) has a bunch of ideas....pharmaceuticals (more pure)...

...
zero-gee pharmaceuticals...


I've said this before on this board: I have worked in biopharmaceutical research for the last 17 years and I have never heard anyone in the industry lament the fact that we can't currently manufacture our drugs in a zero-G environment.

Realistically, it is a total non-issue, not even on the most distant radar screen of the most visionary pundits. It is a solution created by the space industry to a problem that doesn't exist.


So far as we know, there is only one living species in the Universe that has the mental capacity to appreciate its beauty and wonder. Shouldn't preserving its existence by a high priority?

No. So far as we know there is only one living species in the Universe that thinks that the fact that it has the mental capacity to appreciate what it perceives to be its beauty and wonder is somehow significant.

[scotandrsn]

I've said this before on this board: I have worked in biopharmaceutical research for the last 17 years and I have never heard anyone in the industry lament the fact that we can't currently manufacture our drugs in a zero-G environment.

My understanding is that it is not the manufacture of pharmaceuticals, but the research into them. If the active ingredient of a drug can be formed into a crystal where the active site of the chemical structure is exposed, and the chemical you are hoping it will interact with can be formed likewise, it's easier to tell if the ingredient performs as hoped. Such crystals are more easily formed with a regular structure in zero-g.

As I said , that's my understanding. I'd be interested to hear your thoughts on it.

[Laughing Lagomorph]

My understanding is that it is not the manufacture of pharmaceuticals, but the research into them. If the active ingredient of a drug can be formed into a crystal where the active site of the chemical structure is exposed, and the chemical you are hoping it will interact with can be formed likewise, it's easier to tell if the ingredient performs as hoped. Such crystals are more easily formed with a regular structure in zero-g.

As I said , that's my understanding. I'd be interested to hear your thoughts on it.


From what I have been able to learn the research in this area which has been done so far (which I admit is technically fascinating) has mostly been funded by NASA itself. On the ground this is the kind of stuff that is usually done at large laboratories and universities and funded by the NIH or other federal entities. So the best that could be hoped for in the near term would be one arm of the federal government would be paying another for the use of their facilities, which I don't really think would count as commercialization.

Drug discovery is already a very expensive business. Pharmaceutical companies tend to be very conservative and don't normally fund much of this early stage research directly. There would have to be strongly compelling reasons to think that paying to have a particular molecule or class of molecules crystalized in space had a good chance of leading to the discovery of potentially lucrative drugs. I just don't see your average big pharma executive thinking it was a good idea to shoot some of their money into orbit on the off chance they might discover some blockbuster.

The trend in recent years at the big pharmas has been more of a brute force approach, using automation and robots to screen whole classes of related compounds to see which ones could have potential therapeutic actions, and then following up on the ones that seem most promising in early tests. Therefore they don't need to know right away what the active site necessarily looks like, they are only interested in it if it does something potentially useful.

[BrainGlutton]

No. So far as we know there is only one living species in the Universe that thinks that the fact that it has the mental capacity to appreciate what it perceives to be its beauty and wonder is somehow significant.

:confused: What could possibly be more significant?

[Laughing Lagomorph]

:confused: What could possibly be more significant?

My point was of course we think we are significant. Bacteria probably think they are significant too.

[BrainGlutton]

My point was of course we think we are significant. Bacteria probably think they are significant too.

I'm fairly certain bacteria do not think, no more than rocks do. Dogs and cats and apes have some awareness, but thinking that their species has any cosmic significance -- impossible; they can't even comprehend the necessary concepts.

[athelas]

Isn't there some way of coupling reentry of materials to ascent? I could imagine a large supply of rocks (or industrial scrap) being hauled to the terminus of the elevator, then dropped down, while at the same time lifting payloads.

[msmith537]

As most of the source material here seems to be science fiction fantasy, I feel it's necessary for a business guy to check in.

The only use space has for any practical terrestrial application is:
-Taking satelite imagery of Earth
-Unobstructed imagery and other scientific analysis of anything not on Earth
-GPS and other communications

and that is pretty much it.

Space tourism is not a viable industry in any form. It is an indulgance of a handful of super wealthy attention seeking people. There will not be hotels in space unless there are also permenant colonies in space. Which leads me to my next statement:

There will not be permenant colonies in space. As crowded as Earth gets, you could at best put only a small fraction of people in space. It will take far more resources to maintain a colony of 100,000 people in space than it would take to maintain them here on Earth. And since all those resources come from Earth anyway, there is no benefit. If you could create self-contained habitats of 100,000s or millions of people, you don't need to put them in space anyway. You could build them here on Earth.

And speaking of resources, there is nothing more impractical than mining asteroids for nickle or iron. We already live on a giant ball of nickle and iron called Earth. How would you put something likethis (http://users.telenet.be/jeantje/uploaded_images/berge_stahl-713887.jpg) in orbit to mine asteroids and deliver it's cargo safely back to Earth?

Not with a "space elevator". Ok, so you can get stuff to and from Earth orbit. Great. Now what? There's now a new moon in the form of a 300,000 ton ore carrier in orbit. You still need figure out how to move the damn thing around the solar system. I think that 50 trillion dollars might be better spent elsewhere.

[Squink]

and that is pretty much it.Nah, there's room for some smale scale, high value product manufacture. Things like space beads (http://64.233.167.104/search?q=cache:rAA1HBUvrIsJ:nvl.nist.gov/pub/nistpubs/sp958-lide/371-374.pdf+%22space+beads%22&hl=en&gl=us&ct=clnk&cd=1&client=firefox-a) and catalyst substrates made of foamed metal.

[BrainGlutton]

There will not be permenant colonies in space. As crowded as Earth gets, you could at best put only a small fraction of people in space.

In the age of European colonial imperialism, colonies never really relieved population pressure in Europe, either. That's not what they were for.

It will take far more resources to maintain a colony of 100,000 people in space than it would take to maintain them here on Earth. And since all those resources come from Earth anyway, there is no benefit.

Why would the resources have to come from Earth?

And speaking of resources, there is nothing more impractical than mining asteroids for nickle or iron. We already live on a giant ball of nickle and iron called Earth. How would you put something likethis (http://users.telenet.be/jeantje/uploaded_images/berge_stahl-713887.jpg) in orbit to mine asteroids and deliver it's cargo safely back to Earth?

The point is not to deliver the materials to Earth, but to deliver them to Earth's immediate neighborhood for use there. The space elevator just makes it possible for humanity to get a permanent toehold off Earth's surface.

[E-Sabbath]

BrainGlutton's got a point. The argument msmith537 is pretty much identical for both space and the Americas. Certainly, you can ship gold back, but we see how much good that did in the long run for Spain. The real money is moving onwards and upwards.

[BrainGlutton]

How would you put something likethis (http://users.telenet.be/jeantje/uploaded_images/berge_stahl-713887.jpg) in orbit to mine asteroids and deliver it's cargo safely back to Earth?

You don't put it in orbit, you build it in orbit. Assuming you actually need a cargo ship, as opposed to nudging a desired asteroid in the direction where it's needed and then grabbing on to it once it gets there. But once there's enough manufacturing hardware in orbit, you can build anything big you need out of space-derived materials -- build it in free fall, with humans and/or teleoperated robots.