Geoff Landis has a paper out on novel approaches to space solar power systems.

One of the reasons I'm skeptical of lunar He3 for fusion as a viable space based business is the competition from SPS. If you can put enough infrastructure on the moon to process the enormous quantities of regolith needed to extract He3, you can just as easily churn out huge numbers of SPS satellites. Unless there is some unforseen showstopper with SPS (and the only one I can think of is possible long term environmental effects due to the microwave beam, but that seems unlikely), then SPS construction will win over He3 fusion. We can do SPS with current technology. We're not even close to being able to do fusion with He3, and we won't be for probably two decades. That's just fusing the He3, not doing it cheaply enough to compete with other power sources.

I'm slowly churning through a detailed piece on fusion which will hopefully clarify a lot of these issues, but I'm a having trouble making the piece not suck, so don't hold your breath. Hopefully I'll get unstuck soon.

Concerning space solar power, if improved technology allows more efficient panels, why not spread those panels in places like the Sahara or Saudi Arabia? Way cheaper, right?

My biggest complaint about the space solar power approach is the assumption that space resources exist to be brought back to Earth, for Earth's benefit, like plunder. This reminds me of the Spanish style exploitation of South America versus English style expansion in North America.

Spain exploited South American gold for return to the Mother country and ultimately failed as a colonizing power. England build settlements and expanded its economy to incorporate distant lands (America) based on trade with the settlers, not based on bringing plunder back home. The goal should be to expand the human race out into the solar system as free societies not subservient to Earth, either politically or economically.

Anyway, LEO power satellites (if technically feasible) are an awesome idea if they truly can deliver power for less than spreading those same solar panels in the desert or on oil rigs in equatorial waters. Safer fission reactors may be more efficient. Its a bean counting question.

That said, such projects do not really advance the objective of expanding our human presence out into the solar system.

Bill - you are right that it's bean counting that makes the difference. That's the whole issue, both for lunar He3 (and there are other reasons to believe the He3 doesn't win the bean counting game for fusion, even without competition from SPS), and for any ET resource exploitation effort.

On the Spanish vs. English models of colonization: I think the historical analogy isn't quite right, since the Spanish did colonize to a certain extent, but in a very different way - they weren't just sending stuff home. The English model of going for land and liberty is a better one, though. A lot of what the Spanish did was import semi-feudal social models, while the English came over in part to engage in social experimentation.

Either way, the early drivers of the age of exploration was a quest for high value goods to return to the home country, and it's reasonable to do that in space. He3 won't serve the role of spices from the east, but Platinum group metals might. Once there is a bit of infrastructure based on importation of goods it becomes cheaper to send people with the aim of staying permanently.

Concerning space solar power, if improved technology allows more efficient panels, why not spread those panels in places like the Sahara or Saudi Arabia? Way cheaper, right?

Cheaper, and way less effective. They don't get continual sunlight, and you still have to get the power from them to where it's needed.

"Its a bean counting question."
Not entirely. Otherwise coal power would have no competition at all.

"That said, such projects do not really advance the objective of expanding our human presence out into the solar system"
Thats wrong, because such projects would immensely help to establish the basic infrastructure needed for humans to expand outward. First, via creating markets and ironing out certain essential technologies in LEO.
Second, nothing constrains the idea to LEO only, it could work as well on martian orbit or anywhere in inner solar system.

Rand writes:

B: Concerning space solar power, if improved technology allows more efficient panels, why not spread those panels in places like the Sahara or Saudi Arabia? Way cheaper, right?

R: Cheaper, and way less effective. They don't get continual sunlight, and you still have to get the power from them to where it's needed.

= = =

Use it to crack water into H2 for fuel cells then ship. But it is still a bean counting question.

If micro-wave sats are cheaper, do it!

As for coal, the environmental degradations from burning coal merely are those beans we choose to ignore and refuse to count.

= = =

This discussion (Spanish-style versus English style and the like) is valuable whether I am right or wrong. :-)

My biggest complaint about the space solar power approach is the assumption that space resources exist to be brought back to Earth, for Earth's benefit, like plunder. This reminds me of the Spanish style exploitation of South America versus English style expansion in North America.

I don't see this at all. Ultimately, Earth is going to continue to be the most important customer of products in the Solar System for some time to come. It makes sense to consider space projects which serve Earth. Imperialism has nothing to do with this.

I think we're a long ways from SPS. If we don't routinely put unsubsidized photovoltaic cells on rooftops (ie, right next to the demand), then why should we build them in space? I don't see the economic arguments to justify this yet.

The problems with fusion power seem even more difficult. We need a source that not only generates more power than it consumes, but so cheaply enough that it can be a competitive source of power.

Karl, like you, I do not believe solar power sats will prove economically viable. We will find cheaper ways to make power on Earth. If I am wrong, well okay, I will happily pay SatConEd and grin.

As for the larger issue, if there are business models that allow the exploitation of space resources at a profit, people should just do it, ASAP.

Have at it, I won't complain. ;-)

Zenit-2 is less than $1500 per pound to LEO. Today. No revolutionary breakthroughs are needed for lower cost Earth to LEO.

SpaceX has done some hairy knuckled engineering and made a new turbopump for their Merlin engine. Bully good show. Now, no more excuses.

But my opinion is that business models based on going out there and bringing stuff back won't make a profit. If I am wrong, and someone does it and proves it? Cool! I have been wrong before and will be wrong again.

But launch costs are fairly cheap and no one seems to have a viable plan to go out there and bring stuff back and make a profit without a government subsidy.

My opinion is that we should look at going out there and staying out there to grow the overall size of human globalized (sic) economy. Like the National Space Society said to the Aldridge Commission, settlement is the mission critical goal. Profit will follow in the trillions.

Exporting platinum to Earth is insufficient to pay for going out there but it would greatly offset the cost to do it, if someone wanted to for other reasons.

I believe SPS have a better chance at being viable for use in space-to-space power transmission. If a giant LEO hotel or a Lunar mining base needs power then it could be bought from the SPS providers. To make this an economically realistic proposition we would have to have substantial off world industry, so it will take some time before we reach that point. Once substantial space-to-space beaming of power is commonplace, space-to-earth power beaming will be provided as an afterthought. It will still have to be more competitive than coal, that will be tough to do. It may only serve as a niche power solution on Earth for remote locations.

I agree the ultimate goal is colonization, but the immediate goal is to get there.

Having loot at the end will probably be the only thing to justify the building of infrastructure to the corporate types who control the non-governmental money spigot, and who also influence governmental spending.

We need them more than they need us at this point in time.

Rich

"But launch costs are fairly cheap and no one seems to have a viable plan to go out there and bring stuff back and make a profit without a government subsidy."
Think service industries.

BTW, does anyone think that first nuclear power station that got built was immensely profitable ( especially when compared to equal sized coal station ) ? Then why build it ?

I suppose a space hotel would be a service industry business.

A space hotel dedicated to tourists (and amateur science) would be a marvelous incentive for Earth to LEO lift capabilities. With Proton and Zenit-2 the cost of orbiting a TransHab based hotel is far less than might be expected.

Name rights alone (Hilton? Hyatt? whatever?) should be worth a few hundred million dollars.

Then use Soyuz for now to gain access with the goal of motivating Elon Musk to man-rate Falcon V ASAP.

There appear to be plenty of people willing to pay the going Soyuz rates to get into LEO and when SpaceX comes on-line Musk can undercut the market and take business from Soyuz.

= = =

I am pleased Bigelow appears to be going in exactly this direction.

Andrew, do you expect He3 breakeven in 20 years, or do you just mean getting it to fuse at all in a reactor? And do you really think it has much advantage over other fuels, especially if it becomes possible to fuse "hard" fuels?

On asteroid retrieval: The cost of bringing stuff BACK isn’t very dependent on launch costs, especially for high value material. Just use some ablative heat shielding (possibly made from the asteroid, it doesn’t have to be that good) around some foamed metal (or whatever) and drop small balls of the stuff in a known area of the ocean, like Apollo capsules.

But I expect that lunar or asteroid resources will first be used to reduce the cost of space structures. It will need that at least before SPS has a chance to be competitive, but you don’t need anything as big as SPS to make lunar/asteroid mining start to look very attractive, even if launch costs get down to merely stratospheric ($100 a pound or so).

D3He produces much less neutron radiation than DT. It's the difference between a reactor in which the first wall has to be replaced every few years, vs. every few decades.

The 'hard' fuels (H + Li or H + B) appear to be impossible to burn in magnetic fusion reactors -- the bremsstrahlung losses at the temperatures required are simply too large.

I disagree with the statement that 'we have the technology' to build SPS, unless that quoted phrase is taken very, very generously (as in, we understand in principle how to do it, never mind all the little engineering details.) In that sense we have the technology to burn 3He, too -- just scale up magnetic confinement reactors enough and they will ignite. That wouldn't be economic, but then we can't build SPS economically today either.

Paul - We have the technology to do SPS in the sense that all the critical technologies have been demonstrated. There is some tricky engineering in building really big satellites, but there are no obvious showstoppers. The engineering is hard, but it's engineering, not physics.

On the fusion front, we don't even know how to build a first wall that can take reactor relevant conditions for extended periods of time. We don't understand the physics of magnetically confined ignited plasmas - that's not a technology issue, it's a physics issue.

VR - when I say 20 years for He3 fusion I'm not anticipating we *will* do it in that time, just that an agressive research program could get us close to doing it in that time, assuming no major surprises. That's just at the research reactor scale, mind you - not commercially viable reactors on the grid. As it stands the DOE plan for the first commercial demonstration reactor envisions 35 years of development, and it assumes a D-T reactor. I think if fusion is ever commercially viable it will be D-D, but that's a different post.

Yes, SPS is primarily an engineering (and political) problem, which includes the engineering necessary to make it economical. All of the technologies in it are probably what NASA would call Technology Readiness Level (TRL) 2 or 3. It's been demonstrated in the lab, but not in the environment, at that scale.