The next frontier
Posted by aogFriday, 26 September 2008 at 19:42 TrackBack Ping URL

An interesting experiment in Hawaii involving beaming power via microwaves. This is one of the key technologies for building orbital solar power systems. This leads back to a question Skipper asked a while back

Similarly, solar system tourism might be plausible, but solar system colonization, never. What possible point could there be? (Unnamed resources don’t count).

I do not think I have ever claimed unamed resources, but here is one named — energy. Once OSP systems are in place, other things will happen as a natural result. For instance, high value industrial processes that need energy and vacuum. Those are not feasible now, but once an OSP is in place, it’s a very different story. I expect the majority of manufacturing to move off planet over the next couple of centuries, lead by the expansion of OSP. After manufacturing comes the search for raw materials, available more cheaply on the Moon or from the planetoid belt. Lots of workers will tend to mean lots of families as well, until there is a population that is simply used to living in artificial space habits. They may well come to regard Earth the way we think of vacationing naked in deepest Africa, as place where “necessary” conveniences are missing and things are completely uncontrolled.

It may also be that space habitats will take over as the lodestone of the achieving class, as Earth increasingly becomes a politically correct statist backwater. That’s not as clear cut as the general pattern of development described above, but hardly implausible. Even without that, solar space will become a place where people can get rich, and that’s all the draw you really need.

Comments — Formatting by Textile
cjm Saturday, 27 September 2008 at 19:30

Outland

David Cohen Sunday, 28 September 2008 at 17:46

Skipper’s position is probably correct if the cost of getting stuff into orbit remains prohibitively high. After the space elevator, however…

David Cohen Sunday, 28 September 2008 at 17:48

I should probably add, though, that I’m skeptical environmentalists/agw-ists will let us beam microwaves through the atmosphere at the levels necessary to transfer significant amounts of energy.

Annoying Old Guy Sunday, 28 September 2008 at 18:32

There’s no fundamental physical reason for costs to orbit to be as high as they are, it’s an engineering problem.

As for the microwave power density, it’s not that large compared compared to sunlight, actually. It’s better because

  1. It doesn’t vary during the day (e.g., you get noon equivalent 24 hours a day)
  2. Conversion efficiency is much higher
  3. The receiving rectenna is much cheaper per square meter
  4. Land under the rectenna can be use for other things, instead of being plated over

Birds can fly through without noticing. Airplanes are more of a problem, although if the power satellites are in geosynchronous orbit, it’s no different from avoiding a tower.

Hey Skipper Monday, 29 September 2008 at 01:29

There’s no fundamental physical reason for costs to orbit to be as high as they are, it’s an engineering problem.

That is the problem’s problem.

Going from theory to reality makes escaping Earth’s, never mind the Sun’s, gravity well prohibitively expensive.

But never mind that, my original point still applies. All production processes are becoming more input, including energy, efficient over time. I don’t expect that will lead to an endpoint where humans can produce everything with nothing, but I see no reason to suspect humans cannot produce everything humans need with much less energy than already hits Earth from the Sun.

Then add to that the seemingly inexorable demographic consequences of modern societies: birth rates at or below replacement. Assume for the moment that the engineering problems associate with boosting any significant amount of mass into orbit are overcome within 100 years. By then, Earth’s problem will not be insufficient energy for too many people. Instead, it will be energy beyond measure for people becoming increasingly easy to count.

Which will leave unanswered the question: Space colonization. What possible point could there be?

Annoying Old Guy Monday, 29 September 2008 at 07:56

Actually, escaping the Sun’s gravity well is relatively easy and for moving about the solar system not necessary.

All production processes are becoming more input, including energy, efficient over time

That’s the Green Fallacy, which I am surprised at you raising. One need merely look at history to see that the more effecient something is, the more we do of it. Can you name one energy efficiency ever that lead to an overall decrease in energy consumption?

Even if not, why wouldn’t there be a shift to OSP if it is, in fact, cheaper? Isn’t that what capitalism does?

cjm Monday, 29 September 2008 at 18:20

relocating the undesirables from earth to outer space has a lot to recommend it.

Annoying Old Guy Monday, 29 September 2008 at 18:55

No, no, the meek shall inherit the Earth. The rest of us will escape.

Hey Skipper Tuesday, 30 September 2008 at 00:12

AOG:

Escaping Earth’s gravity well is not easy. We can scarcely shift something the size of a sub-zero refrigerator to Mars, and we sure as heck aren’t getting it back. I hate to be a nattering nabob of negativity, but I see no reason to think that propulsion systems have not come very close to reaching the same diminishing returns that aircraft already face.

Yes, I know there are notional designs that say I am wrong. However, for those designs to reach anything remotely approaching fruition, then the availability of ample energy here on Earth will no longer be an issue.

That’s the Green Fallacy, which I am surprised at you raising.

No, it is not a Green Fallacy, it is a matter of fact. Humans are getting increasingly good at making very valuable stuff out of extremely common materials. Silicon and carbon are the two prime examples. I got a new bike this spring. The one it replaced was nearly all aluminum, with a few steel bits thrown in. This one is probably 60% carbon by weight (frame, fork, seat post, handle bars).

We are not going to run out of raw materials.

Further, sometime in the next fifty years, the Earth’s population is going to start a long term decline.

To what, who knows. But a population of 3 billion within 200 years is hardly out of the question.

Finally, you are resorting to unamed industrial processes. Undoubtedly, there are a few that could benefit from a hard vacuum or microgravity.

But a majority?

And why wouldn’t those processes be completely automated, anyway?

Annoying Old Guy Tuesday, 30 September 2008 at 09:32

I see no reason to think that propulsion systems have not come very close to reaching the same diminishing returns that aircraft already face

I see a big one. If you look at the cost of the energy difference between a kilogram on Earth’s surface vs. one in orbit, it’s a few dollars in electricity. That’s about 4 orders of magnitude less than current to orbit costs. That’s a truly enormous scope for improvement without any presumption of massively increased energy production on planet.

You are also missing my point about the Green Fallacy. It’s not about whether human technology is becoming more efficient. It is whether such efficiency leads to an overall decrease in consumption. You didn’t address that point at all. Further, it’s not about running out of resources, it’s about getting them cheaper. I expect that environmental damage will percieved as more and more costly as time goes on, making orbital industry increasing cheaper relative to planet based processes.

As for unnamed industrial processes that like vacuum, what about digital circut production? Nanotech? I don’t think it’s too much of a reach to see those two as the dominant industries in a century or two.

And why wouldn’t those processes be completely automated, anyway?

Because it would require true artificial intelligence. So you’d still need sentients in orbit. I am not picky about whether they’re human descended or human constructed.

David Cohen Tuesday, 30 September 2008 at 13:43

AOG: I assume that, immediately upon posting, you realized that the fact that there is no logical or probable danger from sending microwaves through the atmosphere is more or less irrelevant to whether the greens would object.

Hey Skipper Wednesday, 01 October 2008 at 01:05

If you look at the cost of the energy difference between a kilogram on Earth’s surface vs. one in orbit, it’s a few dollars in electricity. That’s about 4 orders of magnitude less than current to orbit costs

A great deal, if not all, of that four orders of magnitude happens to be tare weight: that one kilogram of mass in LEO didn’t get there all by itself, after all. It doesn’t seem exactly fair to exclude the means to the end.

It’s not about whether human technology is becoming more efficient. It is whether such efficiency leads to an overall decrease in consumption.

More to the point, it is whether human consumption can be met by human ingenuity from the available resources on Earth. The record on that score so far is very good.

Further, you keep talking about resources, but I haven’t yet heard anything more specific. Precisely what resources are available somewhere else in the solar system that can’t be obtained more cheaply here on Earth?

Keep in mind, of course, that the long term trend for human population is down, probably significantly.

As for unnamed industrial processes that like vacuum, what about digital circut production? Nanotech?

Fine, they like vacuums. Is it cheaper to produce a vacuum here on Earth, or move all the mass required for digital circuit production or nanotech into the vacuum?

It isn’t even close.

Because it would require true artificial intelligence.

Ummm, no, it wouldn’t. No more than it requires artificial intelligence to remotely perform certain medical procedures or fly drones.

Annoying Old Guy Wednesday, 01 October 2008 at 12:09

A great deal, if not all, of that four orders of magnitude happens to be tare weight

That makes a lot of assumptions that you’re not justifying. Just for example, what’s the tare weight for an orbital elevator? Externally laser boost assent? Linear induction boosting? Orbital momentum transfer systems?

it is whether human consumption can be met by human ingenuity from the available resources on Earth.

Not at all. It’s a question of how human consumption can be met most cheaply. And you call yourself a free marketer!

Is it cheaper to produce a vacuum here on Earth, or move all the mass required for digital circuit production or nanotech into the vacuum?

Probably the latter, once OSP is in place. You’re also not taking environmental issue in to account, which are likely to be a bigger factor in the future than tare weight.

No more than it requires artificial intelligence to remotely perform certain medical procedures or fly drones.

Who preps the patient? Who maintains the drones? If you talk about completely automating some industrial process, you need to consider completely automating it. The telepresence systems you note still require a lot of local human intervention to function, and operate with much smaller latencies than available in orbit.

P.S. And of course, the question is not whether complete automation is possible, but whether it’s cheaper.

Robert Duquette Wednesday, 01 October 2008 at 19:37

Methinks you are exaggerating the desirability of living in space. One thing it will not resemble is living on the frontier. I’d say the closest experience one can compare it to is nuclear submarine duty. It takes a special sort of psychological profile to endure six months on a sub. Hyperactive frontier types wouldn’t last more than a week in such a constrained environment. Not to mention the physical toll that low gravity or zero gravity environments would take on long term space inhabitants. I’d say that the sci-fi stories that have prison labor camps on Mars or the Moon hit nearer the mark than having the meek inherit Earth.

Annoying Old Guy Wednesday, 01 October 2008 at 20:27

You think those prisoners count as the meek?

And why wouldn’t life in space more closely resemble living an under sea lab, rather than a military attack vehicle?

Robert Duquette Thursday, 02 October 2008 at 09:21

The “meek” is just a catch-all phrase for the losers of the world.

I wouldn’t assign much difference between an undersea research lab and a submarine from the standpoint of the psychology of living in a very confined space. Living on an Antarctic base throughout the winter (summer) months would compare as well. There are people who are attracted to those kinds of environments, but they are rare. Most people would get “cabin fever” within two weeks of being in even the most luxurious space accomodation. I don’t see many people being able to adjust to living in such an environment for a lifetime.

Annoying Old Guy Thursday, 02 October 2008 at 10:15

Isn’t that what the barbarian hordes said about living in cities?

It all comes down to money. You don’t see that many volunteers for Antartica because it’s more of a hobby. If people were paid, say, $1M/year, I think you’d see a lot more applications.

Robert Duquette Friday, 03 October 2008 at 10:41

Yes, money would be a good incentive, but that just proves my point that living in space, by itself, would not be desirable to the vast majority of people.

Annoying Old Guy Friday, 03 October 2008 at 11:18

living in space, by itself, would not be desirable to the vast majority of people

Obviously. And living in the American colonies was not, by itself, desirable to the vast majority of Europeans. Yet here we are.

Hey Skipper Saturday, 04 October 2008 at 14:12

That makes a lot of assumptions that you’re not justifying. Just for example, what’s the tare weight for an orbital elevator? Externally laser boost assent? Linear induction boosting? Orbital momentum transfer systems?

I didn’t bother mentioning those examples for one of two reasons: the gulf between paper and reality is insuperable, or, because it inverts your argument.

In the second case, linear induction boosting is sufficiently within the realm of the possible that there is no particular reason to believe it can’t be done.

To anything that can go from 0 to 17,000 mph in a couple miles, and not get squashed in the process.

But all of those things leave you with the same problem that most asserting interstellar travel is possible ignore: once up there with an orbital elevator, et al, how the heck does one get back down?

Not at all. It’s a question of how human consumption can be met most cheaply. And you call yourself a free marketer!

I am a free marketer, and I don’t think we are ever going to find anything that will allow cheaply transferring significant mass into and out of earth orbit.

Which means that no resource you can imagine will be more cheaply available in space than on earth.

Which reminds me: what resource is on the moon, or any asteroid, or any planet, that isn’t available here in abundance?

You’re also not taking environmental issue in to account, which are likely to be a bigger factor in the future than tare weight.

Actually, I do. The richest, highest consuming countries are also the cleanest. And the least crowded.

Additionally, flying all over the place as I do (South America and Africa excluded), the Earth is not even close to overcrowded, and is ultimately going to see a decrease in population. There are huge expanses on Earth that are far, far more desirable places to be than outer space, and are completely empty.

So, you have failed to identify any manufacturing process that can’t be comfortably accommodated within stringent environmental requirements, or named one resource we can’t readily obtain here.

It is kind of hard to argue against that.

Annoying Old Guy Saturday, 04 October 2008 at 14:51

once up there with an orbital elevator, et al, how the heck does one get back down?

Seriously? Getting down is easy. How do you think the unpowered Apollo space craft did it? If you have an elevator, you just ride it back down.

Which means that no resource you can imagine will be more cheaply available in space than on earth.

I have named several — energy, vacuum, and micro-gravity. Of these, as noted in the original post, energy is almost certain to be the main driver.

ou have failed to identify any manufacturing process that can’t be comfortably accommodated within stringent environmental requirements, or named one resource we can’t readily obtain here.

You haven’t shown that, in the long run, accommodation isn’t cheaper in orbit. It’s kind of hard to argue against that. Just think “NIMBY”, or look up what kind of waste silicon manufacturing generates.

Hey Skipper Wednesday, 08 October 2008 at 13:01

Seriously? Getting down is easy. How do you think the unpowered Apollo space craft did it? If you have an elevator, you just ride it back down.

Well, I must admit to some ignorance here. I have absolutely no idea how the unpowered Apollo space craft left lunar orbit.

Regarding a space elevator, getting down is no easier than getting up. Both require a significant amount of power that must be externally applied:

Both power and energy are significant issues for climbers- the climbers need to gain a large amount of potential energy as quickly as possible to clear the cable for the next payload.

Nuclear energy and solar power have been proposed, but generating enough energy to reach the top of the elevator in any reasonable time without weighing too much is not feasible.

The proposed method is laser power beaming, using megawatt powered free electron or solid state lasers in combination with adaptive mirrors approximately 10 m wide and a photovoltaic array on the climber tuned to the laser frequency for efficiency.30 A major obstacle for any climber design is the dissipation of the substantial amount of waste heat generated due to the less than perfect efficiency of any of the power methods.

Even granting every one of the required assumptions — cable strength in particular seems a paean to wishful thinking — cost to orbit will still be over $200 per kilogram.

So when I insist upon naming resources, that list has to be meaningful within the cost constraints.

There is no reason to believe that the technology will be available for something like a space elevator, while leaving Earth itself with insufficient energy.

Similarly, AFAIK, there are no industrial processes now, or envisaged, that require a vacuum volume so large that it is cheaper to bring the process to space than it is to bring space to the process.

That leaves microgravity. There may in fact be things that are possible only in microgravity, but I haven’t heard of any, never mind any for which the payoff exceeds the cost, even at $200 per kilogram.

You haven’t shown that, in the long run, accommodation isn’t cheaper in orbit. It’s kind of hard to argue against that.

Actually, that shoe is on your foot. No space advocates have demonstrated that, for two of the three resources you mention, their opportunity cost on Earth exceeds that in space. As for the third, that is speculation in its purest form: insisting that some valuable process requiring microgravity exists, simply because microgravity itself exists.

Just think “NIMBY”, or look up what kind of waste silicon manufacturing generates.

Okay, granting that silicon manufacturing generates serious waste, and further granting that it is impossible to deal with, what happens to that waste in Earth orbit?

I’m not forgetting the rending of garments and gnashing of teeth accompanying the Chinese blasting just one of their satellites. Something about orbital debris?

So I am left wondering what resource, other than microgravity, will be insufficiently available here on Earth to justify even the lowest to orbit costs (noting that the cost to orbit did not include getting anything back …).

As for microgravity, on current form, it is on the resource list not because it is actually required, but rather that it can’t be had anywhere else.

Annoying Old Guy Thursday, 09 October 2008 at 14:34

Did you read the article you cited? For one, it noted this —

For returning payloads, atmospheric reentry on a heat shield is a very competitive option, which also avoids the problem of docking to the elevator in space.

All of the other discussion about climbers and energy requirements concerned ascent. Which was my point, getting down is easy. As for Apollo, the payloads don’t need to leave lunar orbit unless you’re planning on a cable much longer than the standard design.

About this —

that list has to be meaningful within the cost constraints

Clearly, but then you follow with this

There is no reason to believe that the technology will be available for something like a space elevator, while leaving Earth itself with insufficient energy.

which completely ignores cost constraints and mentions only availability.

As for the other industrial processes, I have carefully noted all along than my outline presumes the existence of orbital solar power stations. Therefore cost estimates that do not presume that and are based on developing a completely independent orbital transport and its costs are irrelevant.

I also have to say, it’s a bit amusing having this conversation with someone who flies for FedEx, of which many people said very similar things when it was starting up. “Who needs packages shipped around the globe overnight? It will never be affordable anyway”.

Hey Skipper Friday, 10 October 2008 at 05:41

Actually, I did read the article. And, as per my confusion with unpowered Apollo spacecraft exiting lunar orbit, I am also completely confused as to just how that payload in Earth orbit, no matter how it got there, is supposed to slow its orbital velocity sufficiently so as to be able to use the Earth’s atmosphere for a reaction mass.

Without a power source, that is. Last I checked, the space shuttle uses a heat shield for re-entry, but, powerless though it might be on descent, uses heavy engines and fuel it hauled into space in the first place to slow down. Getting down is “easy”, but at the expense of tare weight.

Which leads directly to your citing people’s mistaken notions about air freight as somehow supportive of your argument.

On even our longest flights — 13 hours plus — the payload is something over a quarter of the tare weight (weight of aircraft plus fuel), and the operating expense per pound of payload per flight hour ($9000 fuel, $3000 everything else, 150,000 pound payload) amounts to only about eight cents. For an average 8 hour flight, that amounts to sixty-four cents per pound of payload.

So the question Fred Smith had to answer was if there was any freight to be had that was both time-sensitive, and sufficiently high value to make sixty-four cents worth it.

Well, duh. All manner of things fit that bill. (And, if you had thought about it, many people, whoever they might have been, would have realized that if flying people makes economic sense, then flying freight is a no brainer.)

Which, in turn, sharpens my point against the whole enterprise. Even granting all manner of magical thinking — the elevator cable is reminiscent of models used to demonstrate principles in physics, one being “imagine a massless, perfectly stiff bar …” — getting into, and returning from, space causes the payload : tare weight ratio to plummet, while costs go into orbit.

The putative space elevator requires about $100 per pound of total weight to get into orbit. Even if payload : tare is the same as for aircraft, that means at least $400 per pound. That assumption, of course, is very generous, because the weight of the power source and heat shields, and the cost of fuel, for re-entry are completely ignored.

So the question for you is, what can space provide that Earth cannot that would justify $400 per pound payload? (Completely ignoring, for the moment, the cost of getting whatever infrastructure is required into space in the first place).

The problem only becomes worse as the pencil gets sharper — $400 per pound of payload is an extremely generous estimate.

There is no need to go to space to get energy. Vacuums are far cheaper to create on Earth, and don’t have the niggling problem of atomic oxygen to deal with. That leaves microgravity.

As the ISS has shown, the list of such high value processes requiring microgravity is:

[crickets]

Hey Skipper Friday, 10 October 2008 at 05:43

BTW, I forgot to add that Stephen Hawking recently wrote what has to be the lamest ever justification for people spreading into space.

Annoying Old Guy Friday, 10 October 2008 at 08:49

I am also completely confused as to just how that payload in Earth orbit, no matter how it got there, is supposed to slow its orbital velocity sufficiently so as to be able to use the Earth’s atmosphere for a reaction mass.

With a very small motors, or a shove from an orbital station. You don’t need to shed much orbital velocity. In fact, you don’t need to shed any at all, as long as the new orbit interests the atmosphere.

The putative space elevator requires about $100 per pound of total weight to get into orbit. Even if payload : tare is the same as for aircraft

Why would it be the same as aircraft instead of the same as a train? It’s far more like the latter than the former.

I still see energy as the primary compelling drive for industrial space activity. Other things come along once the infrastructure is in place. I see total energy consumption rising for the indefinite future, at least millenia, and so moving generating capacity off planet will become ever more attractive.

Hey Skipper Sunday, 12 October 2008 at 20:45
With a very small motors, or a shove from an orbital station …

Which reminds me of a line from The Holy Grail, alleging that small rocks float.

Yes, a small motor would deorbit a payload.

Eventually, with an inverse ratio between eventuality and smallness. Which puts the whole problem into a square corner: some unamed process is so valuable that it is worth $400 per pound, yet people will be quite happy to wait a long time to get back.

And about a shove from an orbital station — how does that work? Without, that is, some power source to counteract the orbital station’s subsequently increased momentum. The weight of that power source must be, of course, charged against the space elevator.

Why would it be the same as aircraft instead of the same as a train? It’s far more like the latter than the former.

Justification, please.

I think any form of space travel will be much further along the tare : payload spectrum than aircraft — remember heat shields? The energy making the heat shield necessary in the first place had to come from somewhere …

I still see energy as the primary compelling drive for industrial space activity.

You have completely lost me here. This sounds like an assertion that energy is available only in space. That has to be wrong. Ignoring, for the moment, night on Earth anything an OSP can do in space it can also do on Earth, and far more cheaply. And it also ignores the very real likelihood that genetic engineering will (maybe already has) create bacteria that effectively excrete stored energy in fluid form.

Pointless to do in space, does away with the nighttime problem, and would the ultimate in recycling.

Why do you presume that OSPs could provide energy more economically than terrestrial options?

I still see energy as the primary compelling drive for industrial space activity. … I see total energy consumption rising for the indefinite future …

Clearly, I don’t see energy as the compelling drive for industrial space activity, because I can’t think of anything (nor have you provided any examples) of a process that would be more efficiently performed in space than on Earth. The overhead for orbital production would be, well, astronomical.

Also, I don’t see energy consumption for the indefinite future.

First, as I noted above, the human population is almost certainly within fifty years of starting a significant, long term, decline.

Second, using personal experience as a baseline, I don’t think Americans today are using more energy per capita, or per unit GDP, than forty years ago.

Think about houses: better and more insulation, double paned windows, and vastly more efficient HVAC systems.

And cars: more power and better fuel economy every year. When an effective alternative to the poppet valve engine comes along, the consequent increase in thermodynamic efficiency will slash transportation related energy costs.

Computers: I’ll bet the single biggest energy drain for my computer at home was the CRT monitor. Not anymore.

In the medium term, we will use more energy as capitalism makes more of the Earth’s inhabitants like those who live in the West.

However, past that, the decrease in population, combined with greater energy efficiency, means energy consumption will reach a peak, then decline with population.

Annoying Old Guy Sunday, 12 October 2008 at 22:53

How long is long? A day or two? Even very small motors can de-orbit in that time frame, since almost all of the braking is done by the atmosphere. As for a shove off a platform on an orbital elevator, the increased momentum is transferred to Earth via the orbital cable. This is particularly easy if the payload if shoved straight down. If to the side, then you can just alternate sides.

I thought it obvious why an orbital elevator is like a train and not like an airplane, but here you go

  1. Elevator cars and trains use tracks, airplanes don’t.
  2. Neither an elevator car nor a train requires force or velocity to maintain position. An airplane does.
  3. Elevator cars and trains can go arbitrarily slowly. Airplanes can’t.
  4. Elevator cars and trains can transfer momentum to an outside object directly. Airplanes can’t.

An orbital elevator is basically a train track that goes up instead of across. Can you list a single way an orbital elevator car is like an airplane that does not apply to a train?

anything an OSP can do in space it can also do on Earth, and far more cheaply

Not at all. Ignoring transportation costs, it’s enormously cheaper to gather solar power in space. Want an extra 2000 km^2 of sunlight gather surface? No problem, just roll it out. Try that on the ground. I can also discuss the costs of weather proofing as well, which just don’t apply in space. Or having to make structures stand up to 1G continuous acceleration. No habitats of endangered species will ever be impacted, nothing will clutter up anyone’s view.

Concerning energy use —

the human population is almost certainly within fifty years of starting a significant, long term, decline

Faster than non-Westerners will acquire Western levels of wealth and, of course, Western levels of power consumption? China and India have what, 10 times the population of the USA, and would increase their power consumption by at least an order of magnitude? How much population decline do you need to compensate for that? You wave that issue off rather blithely given its truly massive impact.

I don’t think Americans today are using more energy per capita, or per unit GDP, than forty years ago.

Let’s check. I can’t find national stats right off, but I did find the data for Illinois. I’ll look at 1960 vs 2000 to align with census data and check total electrical power consumption. 1960 gives 467T BTU for 10M people or 46.7B BTU per capita. 2000 reads 1875T BTU for 12M people, or 626B BTU per capita. More than an order of magnitude increase. Good luck with that efficiency thing!

Hey Skipper Wednesday, 15 October 2008 at 12:47
As for a shove off a platform on an orbital elevator, the increased momentum is transferred to Earth via the orbital cable …

That cannot possibly be true. Again ignoring for the moment whether a cable can actually be made, the cable will not possess the infinite rigidity so beloved of simplified physics models. It will be a very, very long, very very undamped spring.

So, sure you could push a mass off a platform, but only if the mass is either tiny with respect to the platform, or the push is quasi-static. Either way, getting any meaningful mass back to Earth would take darn near forever.

As a side note, I re-read the Wikipedia article (which I grant is not the font of all wisdom, but I am very short on time today). It didn’t even begin to mention what might be the most obdurate obstacle of all, which is a very high bar indeed: the moon.

I thought it obvious why an orbital elevator is like a train and not like an airplane, but here you go.

The reasons you list are not obvious because they exclude things that are alike, and include things that are not, while ignoring what is by far the most significant discriminator: the z-axis.

Ships and trains are more alike than either are to anything else. Yet ships don’t use tracks, require force to maintain position, and cannot go arbitrarily slowly. In fact, by your schema, ships are like planes.

However, in the way that matters, motion in the z-axis, they are entirely different. That is what makes aircraft transportation so much more costly per pound than by train, and especially by ship.

That is precisely the way an orbital elevator is like an airplane, but much more so. The numbers I cited for aircraft, conservative because I used only 90% of the plane’s actual carrying capacity, amount to less than $1.25 per payload pound to move something halfway around the planet. In contrast, a space elevator, supposedly the cheapest way into orbit, will cost 300 times as much. And that probably doesn’t include the cost or mass of getting the payload back. (In an airplane, getting the mass back to earth is practically free.)

Want an extra 2000 km^2 of sunlight gather surface? No problem, just roll it out. Try that on the ground.

There are two problems here. First, it is more than just rolling out the material — gathering, moving and using the resulting current requires no small amount of mass.

Second, you appear to assume technological stasis here on Earth. Since we can pretend a cable to space is actually doable, then we can also pretend engineered bacteria that turn any manner of things into liquid fuel. That means more power is available through adding volume, not merely area.

As for weather proofing, that space elevator cable amounts to miles and miles of single point failure, the bottom portion of which must be weather proofed; the upper portion meteorite proofed.

1960 gives 467T BTU for 10M people or 46.7B BTU per capita. 2000 reads 1875T BTU for 12M people, or 626B BTU per capita. More than an order of magnitude increase. Good luck with that efficiency thing!

First off, full points for research.

However, if one was to plot energy use per capita over time, as opposed to just two points, I’ll bet a very different picture emerges: most of history at essentially zero, then a rapid rise to a much higher level, which will then remain essentially static, or even decline somewhat.

In other words, the order of magnitude difference between 1960 and now is undeniable, but I’ll bet if you looked at the trend between 2000 and now, it would be nearly flat. Commuting and air conditioning were the big drivers; both have reached saturation, and are bound to become more efficient.

Faster than non-Westerners will acquire Western levels of wealth and, of course, Western levels of power consumption? … You wave that issue off rather blithely given its truly massive impact.

I’m not waving it off, I am simply taking time into account. Even assuming space elevators are possible, I see no reason to believe routine transportation to and from orbit at $400 on the pound will occur in the next 100 years. During that time, what technological advances will we see in energy production here on Earth? In energy usage?

After all, fuel cell powered cars will be a doddle compared to a space elevator, and will at least double the thermodynamic efficiency of today’s poppet valve engines — from 15% to over 30%.

That alone compensates for a huge increase in personal transportation.

Wide spread LED lighting compensates for a lot more lights. I just replaced the halogen lamps in the rolltop desk at which I am working with LEDs. Same light, probably less than 10% of the power. If touched, the halogens would immediately impose a painful burn. I can leave my hand on these LED lamps indefinitely, and have it scarcely warmed.

Annoying Old Guy Wednesday, 15 October 2008 at 14:50

I would note that first, we are discussing two separate issues, orbital solar power and orbital elevators. These are not the same and neither depends on the other. You seem to be conflating them.

Anyway, let’s look at orbital elevators first.

the cable will not possess the infinite rigidity so beloved of simplified physics models. It will be a very, very long, very very undamped spring. […] So, sure you could push a mass off a platform, but only if the mass is either tiny with respect to the platform, or the push is quasi-static. Either way, getting any meaningful mass back to Earth would take darn near forever.

Why would the cable need to posses any rigidity? You could push off from a freely orbital station. The cable just lets you transfer momentum to the Earth which you can do with a string just as well as a rigid rod.

I also don’t see the “darn near forever” part because you just need to hit the atmosphere at which point it’s overly quickly. If travel times were really critical you could put a secondary station at a few hundred kilometers up and drop from there.

the most significant discriminator: the z-axis.

Why is that true? Why does it make transportation more costly? You just assert this and provide no basis for it. My points 2,3, and 4 go directly to transportation costs. And, as far as I can see, getting the mass back to Earth from orbit is practically free as well.

On to orbital solar power.

it is more than just rolling out the material

Yes it is, the biggest being buying the 2000 km^2 of area on which to put the collectors. Look up some land prices and land use regulations and get back to me on that.

My weather proofing comment applied to OSP not orbital elevators.

Now for energy use.

However, if one was to plot energy use per capita over time, as opposed to just two points, I’ll bet a very different picture emerges: most of history at essentially zero, then a rapid rise to a much higher level, which will then remain essentially static, or even decline somewhat.

I would think that after such an epic fail of your intuition on this subject you would go for a bit more humility. I mean, you picked the time period and I got as close as the data permitted to it.

As it turns out, however, the overall curve looks far more like an exponential which has the long, flat start with the rapidly rising tail, just like we see if we look at actual per capita power consumption. Your argument seems to be that after all of human history going a different way, we, this generation, will see a fundamental unprecedented in history change for no particular reason. We’ve just looked at a 40 year period in which the efficiency of our products and processes increased enormously, resulting in … an enormous increase in per capita energy consumption! Gosh, who would have thought that?

I did, in fact, look at the trend post 2000 in the data and it’s the same growth curve.

from 15% to over 30% […] That alone compensates for a huge increase in personal transportation.

Huge increase? Double at best. You’ve got a couple of orders of magnitude to go, or explain why the rest of the world won’t go through the same energy consumption curve we did in the 1960-2000 time frame. Heck, that would barely cover the expected growth in the USA population, much less the rest of the world.

Also note that you don’t have to show that we will improve efficiency in the future. You need to show that we will improve efficiency at a vastly greater rate than any time in history. Even if we, the developed world, suddenly decide that we have enough and don’t increase consumption, you need those gains just to compensate for the rest of the planet over the next century or two.

Hey Skipper Thursday, 16 October 2008 at 14:54
I would note that first, we are discussing two separate issues, orbital solar power and orbital elevators. These are not the same and neither depends on the other. You seem to be conflating them.

I apologize for being confusing.

You are right, of course. OSP and OEs are not the same. However, the sine qua non of OSP is lift. The reason I have been talking about OEs is that they (at least theoretically) offer the cheapest — hence the most favorable to OSP — route to orbit.

Since you are primarily resting your case upon OSP, you need to address the all-up cost per kilowatt hour of a putative OSP, including the ground stations. What lift cost per pound is required to make an OSP competitive with a similar terrestrial solar power installation?

Anyway, on to OEs: Why would the cable need to posses any rigidity? You could push off from a freely orbital station. The cable just lets you transfer momentum to the Earth which you can do with a string just as well as a rigid rod.

Yes, one could push off from a freely orbiting station, which transfers the momentum to the station. That is nothing more than a rob Peter to pay Paul transfer. The station would require some power source to dissipate the momentum, which needs to be charged against the OEs lift cost.

A cable does not simply allow transferring the momentum to Earth. First, keeping in mind that the payloads orbit is essentially a perfect circle around the Earth’s center of mass, there are two ways to get the payload to intersect the atmosphere, a force opposite to the velocity vector, or a force orthogonal to the velocity vector pointed at the Earth.

The first would displace the OE system laterally, establishing an essentially undamped wave. The second would stretch the cable, which means rebound. Either way, there will be periodic increases in loads on the cable that under static conditions is already stressed past the breaking point of any known material.

That is why it would take darn near forever to deorbit a payload via an OE — to avoid destroying the thing, any force would have to be very small, making the deorbit time very long.

Why is that true? Why does [movement in the z-axis] make transportation more costly?

To save time, I won’t bother explaining why; rather, I shall note that it is apparently ineradicably so. By far the cheapest way to transport mass is via ship, followed by trains, then trucks. All three are roughly similar.

Moving stuff by plane is far more expensive than any of those three, and even the cheapest estimate for putting mass into orbit makes air freight free in comparison.

If there are any exceptions to that rule, I’d be happy to hear them.

I would think that after such an epic fail of your intuition on this subject you would go for a bit more humility. I mean, you picked the time period and I got as close as the data permitted to it.

Yes, I did something of an failure, but less than you suspect. First, I take issue with your assertion growth is exponential. This projection (see figure 17) looks very linear to me. Also, if you look at figure 22, you will note that perhaps my intuition wasn’t completely misplaced. Since 1980, GDP has changed by a factor of two in OECD countries, while the energy used to create that GDP remain nearly unchanged.

Put differently, (see figure 25) the thousands of BTU per 2000 dollars of GDP has been decreasing throughout the world. In the OECD, from around 12,000 to just over 5,000 forecast by 2030.

From the cite:
Another major source of uncertainty in the projections is the changing relationship of energy use to GDP—or energy intensity—over time. Economic growth and energy demand are linked, but the strength of that link varies among regions. In the OECD nations, history shows the link to be a relatively weak one, with energy demand lagging behind economic growth … The pace of improvement in energy intensity may change, given different assumptions of macroeconomic growth over time. Faster growth in income generally leads to a faster rate of improvement (decline) in energy intensity. In the IEO2008 high macroeconomic growth case, worldwide energy intensity is projected to decline by 2.3 percent per year on average from 2005 to 2030
Huge increase? Double at best. You’ve got a couple of orders of magnitude to go, or explain why the rest of the world won’t go through the same energy consumption curve we did in the 1960-2000 time frame.

As the above cite shows, energy efficiency is already significantly increased. There are plenty of examples why; I just picked a couple off the top of my head. Practical fuel cell vehicles getting the equivalent of 100 mpg (noting that modern diesels can get close to 50 already) could make fueling personal transportation practical from renewables alone.

Finally, in regards to OSP, keep in mind the terrestrial alternatives. The US alone has sufficient coal to last for several hundred years. Also, I saw an article about a month ago statingthat Shell has discovered a cost competitive (at ~$120/barrel, anyway) way to recover high quality oil from shale like deposits in the Montana/Utah/Wyoming region. Those deposits alone would replace all the US imports for at least 100 years.

Both of which get the US, and the world, beyond the time when the population will be in long term decline.

How the heck is OSP supposed to be cost competitive with that?

Annoying Old Guy Thursday, 16 October 2008 at 20:22

What lift cost per pound is required to make an OSP competitive with a similar terrestrial solar power installation?

That’s an interesting question. The best estimates now are around Error: WikiVar “500-” not defined1000 per pound but the numbers are very dependent on a number of factors that will be hard to know until we try it. My opinion is that launch costs, like everything, will come down a steep curve once usage goes up. I think the combination will prove irrestible in not too many decades — power plus lower launch costs sparking an industrial boom.

there will be periodic increases in loads on the cable that under static conditions is already stressed past the breaking point of any known material.

If you are going to dispute the basic cable material, you should do that. But if such a cable is possible, then then additional loads from payloads are completely negligible. The mass of the cable would be enormously larger (several orders of magnitude) than any payload. You would also need a vibration damping system anyway to deal with the numerous influences on the cable. Payload induced vibrations would once again be trivial by comparison.

If there are any exceptions to that rule, I’d be happy to hear them.

Freight elevator vs. helicopter? I mean, they both move on the z-axis, so they should be comparable in cost, right?

I take issue with your assertion growth is exponential

Hmmm. Let me quote that article —

Energy demand in the OECD economies is expected to grow slowly over the projection period, at an average annual rate of 0.7 percent

That’s exponential growth. Are you saying the authors read their own charts incorrectly?

As the above cite shows, energy efficiency is already significantly increased.

That’s precisely the point I was making in my last comment. What was the result of that increase in efficiency in the examined period, 1960-2000? A massive increase in energy use overall and per capita. You keep arguing as if I am denying future gains in efficiency. I am not. I am saying that the historical record is that such gains don’t stop growth in energy consumption. Your argument is that, for an as yet unspecified reason, future efficiency gains unlike past ones will lead to decreased energy use. Your article does make some mention of changes in the linkage between per capita energy use and economic growth, but it’s mentioned only briefly at the end and is based on a relatively short observation period.

Hey Skipper Friday, 17 October 2008 at 18:16
Lift cost per pound …

This is where our opinions diverge. Even if lift cost per pound goes to $1000 — presumably only to LEO — the payload (vs. gross weight) cost per pound will be higher. The multiplier can only be guessed. For a space vehicle containing its own energy source and power production, no matter how efficient and reusable, IMHO, a GW : payload ratio of 10 seems optimistic. At the moment, if I understand the numbers correctly, the all-up cost of a Soyuz vehicle, divided by its weight yields $10,000 per launch gross weight pound. Clearly, if one divides all-up cost by payload, the cost per pound is a heck of a lot higher.

But even if the payload cost comes down to $1000 per pound, the question remains whether there is anything that can be done in orbit that adds more than $1000 per payload pound in value over that same thing performed here on Earth.

The most obvious, if only because it is the only one specifically named, candidate is space generated power. I understand the attraction: a ring of geo synchronous power stations beaming power to just about wherever it is needed, absent, perhaps, areas more than 45 degrees displaced from the equator.

Unfortunately, that only makes sense if the cost per kilowatt hour is competitive with the alternatives. So let’s take $1000 per payload pound to geosynchronous orbit as given. To balance the optimism, let’s also presume artificial constraints on nuclear power and fossil fuels go away.

Can orbital power compete with the current US average cost of less than 11 cents per kilowatt hour?.

Limiting ourselves to solar power, there is an astonishing amount of very sunny, very empty, space in the southwest US. Keeping mind that getting the mass of an average car into orbit would cost about $3,000,000, transport costs would dwarf the cost of the generating equipment itself.

That is why I don’t see it happening. For at least the next couple hundred years, terrestrial alternatives will be far less expensive than power from space. (An issue of the Economist from several months ago had an extended report on energy; their conclusion is that there is no end of the stuff if sustained oil prices go above $125/barrel. IIRC applies here.)

But if such a cable is possible, then then additional loads from payloads are completely negligible. The mass of the cable would be enormously larger (several orders of magnitude) than any payload …

You are correct — my mental model was way off.

Freight elevator vs. helicopter? I mean, they both move on the z-axis, so they should be comparable in cost, right?

For a freight elevator containing its own energy supply and power production equipment, the cost gets a lot closer. And I presume you are going to include in the calculation the cost of the compressive structure required to support the elevator in the first place, right?

Hmmm. Let me quote that article —
Energy demand in the OECD economies is expected to grow slowly over the projection period, at an average annual rate of 0.7 percent
That’s exponential growth. Are you saying the authors read their own charts incorrectly?

No, I think you are.

First, the charts give every appearance of being linear of depicting a linear trend.

Second, an average annual rate of .7 percent need not be exponential.

For example: a road rises 3 feet for every 100 horizontal feet. The resulting grade is a very linear 3%. Unless I missed something, I don’t find any reason to believe the authors were talking about anything other than rise over run.

You keep arguing as if I am denying future gains in efficiency. I am not. I am saying that the historical record is that such gains don’t stop growth in energy consumption. Your argument is that, for an as yet unspecified reason, future efficiency gains unlike past ones will lead to decreased energy use.

I am quite sure you are granting future efficiency gains.

I do not think, though, you are fully integrating population trends, efficiency gains, and opportunity cost.

For instance, David has stated that driving is inversely proportional to fuel cost. To a certain extent, that is true: the less it costs to drive, the more we will drive.

Similarly, air travel has become much less expensive (in large part because it has become much more fuel efficient, probably on the order of 50% over the last twenty years), people fly more.

However, given a static population, both those trends must level off. I can’t fly if I am driving, nor drive when I am flying. I can do neither 25 hours per day.

People want detached houses, which become more affordable at larger sizes as HVAC gets more efficient. But larger houses come with their own opportunity costs. Further, people don’t want an infinitely bright house, or room temperatures of 55 degrees in the summer or 95 in the winter.

Also, I am generalizing from personal experience, which I bet mirrors yours. I am not wealthy, but I am very well off. Despite a total energy bill which is such a small portion of my overall budget that I don’t even think about it, I drive much less than I can afford to, don’t heat the house as much, etc.

In terms of BTUs, my energy usage has been flat to slightly negative over the last 15 years. I’ll bet your experience is the same. It is at a much higher level than much of the rest of the world enjoys, but it, like mine, reached a saturation point after which it has remained largely static.

Therefore, for you and me, efficiency gains will lead to fewer BTUs.

Obviously, overall energy usage is going to increase while the rest of the world reaches an energy-dependent activity saturation point.

In the meantime, the inexorable demographic trend is for societies to become wealthy, then see their birth rates collapse. South Korea, despite being a very Christian country, has a total lifetime fertility rate of 1.1 children per woman (explain that, OJ). Japan is nearly as low. China’s one child policy and female infanticide ensures a plunging population. Russia is already there. Absent recent immigrants, the US’s LTF is roughly 1.85.

Consequently, your energy usage scenario is something of a can’t-get-there-from-here. If people are rich enough to be big energy users, there won’t be very many around. It is well within the realm of possibility that many countries will see their populations drop by half within a 100 years.

In other words, whatever increase in energy usage there has been per capita will very likely (at least as likely as $1000 per pound payload to geo orbit) be completely swamped by plunging populations.

Opportunity cost is my argument that there is a saturation point for energy use. Efficiency means that activity saturation point will require fewer BTUs. Plunging head count may very well mean that within, probably well within, a couple hundred years, there are fewer people on the planet then there are in the rich west today.

So, if one accepts the Economist’s article that there is plenty of energy to be had from all manner of sources if the price of oil goes, and remains, beyond $125 per barrel, then I simply don’t see how we get to a point where OSPs are worth the candle when it costs $1000 per pound just to put them in place.

Annoying Old Guy Friday, 17 October 2008 at 20:45

Lift cost per pound

Every cite I have seen of this is payload only, so $1000/lb to orbit means $1000 per pound of payload. That means for $10B you can lift 10 megapounds. $10B not that much more than a large electrical generator costs these days and costs are rising. I have had difficulty find prices, but from $1K to $3K per kW for coal or nuclear plants seems a good rough estimate, which means a 1500 MW would cost $1.5B to $5B (the latter number being the actual cost of an actual 1500 MW generator). I would also note that if OSP construction costs match ground systems, OSP wins big because of fuel costs.

But yes, we disagree on this. If for no other reason than GDP growth acts as a deflator on the number, even absent inflation. I also think that the environmental costs of ground based generation will, in contrast, continue to rise for the forseeable future, another point on which we disagree.

I presume you are going to include in the calculation the cost of the compressive structure required to support the elevator in the first place, right?

No, because you didn’t count the cost of the tracks for train freight costs.

an average annual rate of .7 percent need not be exponential

It is by definition exponential. An exponential series is any series where each term is a constant multiple of the previous term. In this case, each annual energy use is 1.007 times the previous year’s, i.e. each term a constant multiple of the previous.

But what about

a road rises 3 feet for every 100 horizontal feet. The resulting grade is a very linear 3%

Ah, but that’s not the same. The road rises a constant 3 feet each 100’ interval. Each 100’ height is not a multiple of the previous height. If the height had a 3% growth rate, then it would rise about 3.1’ the second 100’, 3.2’ the third, etc. After 2000 horizontal feet, it would be rising 6’ per 100’.

P.S. Here’s a cite for OSP at 8¢ - 10¢ / kwH, although Ben Bova is an enthusiast, not an unbiased source.

Annoying Old Guy Sunday, 19 October 2008 at 09:08

Oh, and hey — you want a candidate for the next big energy consumer, as HVAC was over the last half century in the OECD? Desalination. You heard it here first.

Hey Skipper Monday, 20 October 2008 at 19:02
Lift cost per pound

Your numbers are plausible only if payload costs do, in fact, come down to $1000 per pound.

At the moment, Soyuz launch costs are ten times that. So long as any lift system has to carry its own fuel, oxidizer and engines, than I doubt there will be very much improvement; even $5000 per pound to geosynchronous orbit seems out of reach.

Which leaves something like the space elevator, with a cited cost of $400 per pound, gained by the same expedient a normal elevator uses: not having to lift the power source, along with the load.

Let’s say that such a thing is possible, and, optimistically, its total cost to the first payload (R&D, construction) is $50 billion, or less than 5 years NASA’s annual budget.

How many loads does the elevator have to lift, until the investment cost per pound reaches $4000, to allow even a minimal cost difference versus rockets, and each load is 10,000 pounds, all of it payload? 1,250 loads. Now, I have no idea how much an OSP capable of generating 1500 MW on the receiving end would weigh, but if my running notional math is still correct, 1250 10,000 pound loads amounts to about 6,200 tons. I don’t think that is out of line. However, even if it is high by a factor of two, amortizing development costs, even assuming O&M costs and interest costs on $50 billion are zero, means OSPs will be many times more expensive than their terrestrial counterparts. What does fuel have to cost to make up the difference?

My estimates are, IMHO, very favorable to what is supposed to be the cheapest means to orbit. Double the cost, or halve the payload (thereby doubling the payback time), and combination of cost and time becomes completely unmanageable. Both outcomes are far more likely than not. Even $100 billion to build the first space elevator seems hopelessly optimistic.

BTW, GDP growth is just as much a deflator for terrestrial power as it is for OSPs.

I presume you are going to include in the calculation the cost of the compressive structure required to support the elevator in the first place, right? No, because you didn’t count the cost of the tracks for train freight costs.

Huh? Of course it is included in the shipping cost. Just as every pound of freight FedEx delivers includes the costs of every part of the aviation infrastructure: airports, ATC, charting, training, periodic checks on the aircraft, etc. None of that is subsidized.

But even at the risk of double counting, lets compare the costs for, say, 10 miles of track, and 10 miles of freight elevator.

Ooops. Can’t. No such thing. How about making it more of a like-like comparison: helicoptor to freight elevator. A Bell 206 (the sort of helicopter life flights use) will lift, and hover, 1600 pounds at 8800 feet on a hot (ISA+20C) day. A freight elevator can lift 1600 pounds 8800 feet, well, never.

So, they are not comparable in cost, because there is simply no such thing as a freight elevator that can lift as much, as high, as a helicopter.

Why? because movement in the z-axis gets very expensive, very quickly, no matter how it is done.

It is by definition exponential. An exponential series is any series where each term is a constant multiple of the previous term. In this case, each annual energy use is 1.007 times the previous year’s, i.e. each term a constant multiple of the previous.

Actually, I knew that.

But to resolve the question of precisely what the author meant when saying the words “annual average rate of 0.7%”, only the data itself will suffice.

From the rest of that sentence …whereas energy consumption in the emerging economies of non-OECD countries is expected to expand by an average of 2.5 percent per year (Figure 10). I am going to refer to Figure 9, which is entire world consumption, because it actually includes specific usage numbers per time period. The period-on-period differences from 1980 to 2030, where each period is five years are: 25, 38, 18, 33, 64, 50, 51, 45, 44, 43. If the growth was exponential, each difference between periods would have been greater than those preceding. Not only is that not the case, but the forecast (the last five numbers) is initially flat, then starts decreasing.

Regarding the OECD number of .7% per year, exact values are impossible to obtain from the graph, but if you take as one endpoint 1980, and the other 2030 in figure 10, the only deviation from a straight line is the absolute decrease between 1980 and roughly 1987. After that, the growth line couldn’t be any flatter than if it had been drawn with a ruler.

That is not exponential growth, no matter what the words on the page say.

Oh, and hey — you want a candidate for the next big energy consumer, as HVAC was over the last half century in the OECD? Desalination. You heard it here first.

Rational water pricing is a heck of a lot cheaper than building a bunch of desalination plants, no matter how they are powered.

LEO costs of $500 - $1500 are conceivable, but, absent rampant optimism, geosynchronous lift costs will never be less than multiples of thousands. That simply won’t be able to compete against technological developments in terrestrial power generation — think of house roofs as solar panels — and energy storage.

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