Wednesday, September 30, 2009

Building Things in Space

Structural Fabrication Work
Construction in space, remarkably and wonderfully, is something we know that we can do, because we have done it. And it is worth saying something about, if only as a change from the distressingly popular subject of blowing things up in space.

To be sure, what we do now is only the final stage of assembly, and from kits. We all know how smoothly that can go. Like rendezvous and docking it might easily have been impractical, but it works about as well in real life as it did in Heinlein stories.

Thus we can build our ships in space, as big as we need them to be, instead of having to launch them all up from Earth. In this as in so much else, the ISS amounts to a training mission for deep space travel.

Actual fabrication of structures is another matter, but we are not likely to do it (other than as an experiment), or need to do it, for quite a long time to come. The reason lies in the odd economics of space travel, and Cobb's Law. If orbit lift is cheap, we can bring up the things we need. If it isn't cheap, we aren't up there either.

Cheap is a relative term when it comes to space travel, but I'll resort to my standard rule of thumb and say that with technical and economic maturity the major component parts of a spaceship - hab pods, tanks, drive units, radiator panels; some assembly required - might cost roughly a million dollars a ton, here on Earth at the factory gate. Launching them into space, along with assembly crews, might cost another $1 million a ton, making the on orbit flyaway cost $2 million per ton.

The good news is that this places deep space craft in the same broad range of cost, size for size and mass for mass, as jetliners, of which thousands are in regular service. The bad news is that the lunar spacecraft industry is strangled in the crib. It has no market unless its production cost at the factory cargo airlock can be brought down to twice Earth production cost at the factory gate. That is an awfully tough standard for a new industry on a new planet.

(If lift cost to orbit can be brought down to $100,000 per ton - which calls for the magic of heavy traffic demand, supporting regular flights by production vehicles - even food production is cast in doubt. $450/lb is a lot to pay for cornflakes. But cheap local produce from the ecohab is only cheap after someone has built the hab, and mastered space gardening techniques.)

More complete fabrication in space will grow partly out of special requirements for structures too big to lift and not suited to snap-together construction. But more than that it will evolve from the duct tape side of the equation. People will start modifying pods, authorized or otherwise. Over decades a boneyard of old structures and equipment will accumulate, begging to be repurposed. Orbital (or lunar, etc.) machine shops will appear to do this work.

And the machine shop is pretty much the basis for all industrial technology, a production line being simply a series of machine tools lined up and set up to run a standard job repeatedly.

Once space facilities can fabricate their own structures, the 'supply chain' economics changes. Now the lunar industry doesn't have to compete in the market for expensive prefabricated pods, but for much cheaper rolled aluminum and the like. Raw aluminum currently costs on order of $3000 per ton - even if the lunar cost were ten times greater, it would be cheaper than 'cheap' orbit lift.

A note of caution. As always in space economics there are some devils in the details. Inherently the trip from the lunar surface to lunar orbit and back, a round trip delta v of 3.2 km/s, is much cheaper than from Earth to LEO. A sensible, single stage vehicle can do it. But it will only be cheap when there is enough lunar traffic for frequent service, so that economies of scale can start to kick in.

So a lunar industry may have to start big - perhaps meaning for political reasons - to permit economies of scale in transportation, and likely in production as well. In the pristine world of economics there is no particular reason for this to happen, suggesting that politics might rear its ugly head.

Therein, presumably, would lie a tale.

Image from Atomic Rockets.

Related post: A Solar System For This Century.


Anonymous said...

This was an interesting post. On one hand, it's based upon a subject that has a wealth of data and history that gives a much more accurate and probable prediction of space-based industry. On the other, it shows the complex ballance of such an industry revolving (no pun intending) around what has been for numerous millenia a planet-centered economy.

The industrialization and development of space, weather LEO, LSO (Low Selene Orbit, unless someone else has a better acronym), and beyond depends upon a delicate balance of STO-launches being cheap enough as being economical yet has a profit margins for those doing the transport launches to warrant continued development. I am sure that somewhere in history there was such a balance issue of trade vs transport to which the answer was ultimately solved with cheaper forms of transport, the cargo supporting the paying of the bill, or both.

The only difference being that going into space (at first) is harder than returning to the earth or whatever planetary body the space craft originated. Or so I think would be case.

However, I would see a reason for continued industrialization and development of near-orbit would be a product or industry that simply could not be duplicated or duplicated well planet-side. I remember something about crystals forming more perfectly in micro-gravity and zero-g than upon a planet's surface. Not sure how this would be essential, but maybe in computing?

Course then again, we are talking about an industry that is looking for a product to make.

- Sabersonic

Jean-Remy said...

Saber: yes, crystal growth is more symmetrical in micro-g, and yes, computing, since right now crystals are the new think especially in data storage. Probably the same thing applies to quantum computing, where it would be easier to assemble those molecule by molecule without all that pesky gravity pulling on things. Add to that that it would be easier to build a clean room in space than on Earth, and even more so a vacuum chamber.

M. D. Van Norman said...

At some point in the future, someone living in space will want to build something, and she won’t even consider building it on Earth.

Citizen Joe said...

I think that the current technologies for lifting things into space are based around lifting people into space without killing them. Durable goods could be lifted with less expense, which means you only need to send up people occasionally rather than with each load.

Jim Baerg said...


seems like to lead to the production of aluminum metal from lunar resources relatively early in lunar developement.

If you are making powdered aluminum for rocket fuel, making aluminum sheets as a sideline would be easy.

Even with the recent discovery of water in the lunar regolith, it seems a bit thin to supply lots of H2-O2 rockets, so the Al-O2 rocket would be very useful for extensive operations in the vicinity of the moon.

Rick said...

Course then again, we are talking about an industry that is looking for a product to make.

In the short term, this sums it up. Microgravity manufacturing has obvious potential in the abstract, but I don't get the impression that there is any silver bullet - a process that we know could be done better in space, if only manufacturers had access to it.

I am more and more concluding that the orbit access problem is not really a technology problem. If there were a current requirement for a reusable TSTO we could build one, and we would.

We don't, because world space traffic is only a few dozen launches per year - with current traffic, reusables would not be reused often enough to pay for themselves. (A quibble with Citizen Joe - most current launch boosters were not designed for human missions, and have never been used for them.)

Put simply, the market has no interest in space travel other than putting up satellites, for which current expendables are a cheaper solution than developing new launch vehicles.

Or to put it another way, try finding anyone involved in space access who does NOT care about space travel, and is only doing it for the money. Compare to, say, Iridium. It had $5 billion to blow because it was not pitched to space geeks, but to investors who didn't care any more about space than they care about phones, but thought they could make a buck.

We all basically believe that 'If you build it, they will come.' But the truth is that none of us has an argument that is convincing to anyone but fellow space geeks.

This is why I am coming to think that in the near and mid term the nonprofit sector, especially government, will have to do most of the heavy lifting.

The most promising for-profit activity is likely tourism. If you could offer tickets to orbit for $1 million, I am sure you could sell dozens, probably hundreds of tickets. Perhaps enough to run a space line. But if it is just the equivalent of people who pay to climb Mt Everest, it won't lead to much.

But to make a space line pay you probably also need research labs, university, government, or business, sending up people to do experiments. Which is also where any other profitable activities are likely to come from.

There must be some 'price point' at which people will pony up money, and not just for the spectacular view. But I have no idea what that price point is. Somewhere between $100,000 and $1 million, I would guess.

Citizen Joe said...

By non-human based launch platforms I meant like 20 g sling shots or maglev rail launchers. On the other end, super small stuff could be lifted more slowly using something like the ground based laser powered lift systems. But even for human based lift mechanisms, humans have a great deal of additional mass associated with them beyond their simple body weight. A 70 kilogram box of computer chips is a 70 kg payload. A 70 kg human probably needs closer to 700 kg of support gear to survive the trip.

Jean-Remy said...

If I am correct Rick stated his estimate was the cost of launching one human was roughly the same as 1 tonne of gear.

Rick said...

Yes, a ton per person is my rule of thumb.

But a post at Selenian Boondocks made an interesting point. If you are sending people up on expendable boosters you have to provide the whole capsule.

If you have a reusable orbiter, it already has a cargo bay (plus electrical power, etc.). You just have to pressurize it and fit it with short term life support and some airline seats. Airliners seem to carry about 4 passengers per ton of cargo capacity.

This could be important for a small vehicle like the mini orbiter I outlined - or, prospectively, SpaceShipThree. A half ton payload to LEO is not very useful for launching satellites, but it could ferry a couple of people to the ISS (or a useful half ton in the cargo version), and maybe take up 4 gawkers to a minimum equatorial once around.

Jean-Remy said...

Just thought of something: how massive is the re-entry shield? What if the capsule we sent the people in is actually a part of the station/spaceship you're building, then you can get rid of all that mass, and the mass of the wing and other aerodynamic structure necessary only in reentry. Granted that sort of goes against the whole reusable concept, but if we're going to establish a permanent presence in space, then most likely we'll have more people going up than going down. That's if we want an expanding population is orbit. So why not a variant of the reusable launcher without shield. Or rather, take an expandable launcher and launch a space station/space ship habitat component with its crew?

Anonymous said...

It seems to me that when the population in orbit reaches some point (lets say a 100 or so), then they may nery well need and want a cheaper supply of 'stuff'...and if getting some of it from Luna is substantually cheaper then shipping it up from Earth, then a Lunar-based industry could develop to supply some of those things...aluminum, oxygen, silicon, what-have-you that can be mined and refined on the Lunar surface. Shipping costs from Luna to LEO should be much lower, so more compeditive; a Lunar colony could have the mining company, the LEO supply manufactering company, the rocket building company, and the local colony-support company to employ people in the colony, and in turn supports the people in orbit...allowing more people to move into orbit, ect. The main problem, in my opinion, is getting to that 'tipping point' of population in orbit. A university in orbit, or a satellite/probe building and refurbishing company based in orbit might be the way to go...profit and geekiness combined.


Rick said...

Jean - Surface to orbit passenger craft are so specialized that I doubt it would be worth it to modify hab compartments to carry people up one time.

Deep space is a different matter. There's no reason a habitat intended for, say, Ceres orbit couldn't be built in Earth-Moon space, with a drive and tankage added for it to make the trip. It can go on a slow orbit, because it is intended for permanent occupancy anyway.

Ferrell - It is all about 'tipping point.' The first thing likely to be shipped, by far, is propellant, because you need a lot of it to get around, even in Earth orbital space, and it is inherently rather cheap stuff. Other industries will then grow up around, and to provide support to, the fuel industry.

I like the idea of an orbital university, because it supports a broad range of activities, and it is not under immediate pressure to show a direct profit.

Anonymous said...

Actually, these days universities are extremely cost focused, being run much like a business.

I'm not sure that they would ever be able to justify the cost of having a permentatly manned station compared to the benefit.

A university being involved in a government run program, that I could see.

Anonymous said...

With modern communications universities (And colleges, polytechnics, etc) are being pulled in two directions. The certification and pure-theory diploma courses can be delivered very effectively on-line, and the students don't really need a classroom to pick up the material. Athabasca University is an early-adapter for that trend. But the sciences, arts, and humanities all benefit from group settings and free and open exchanges of ideas (Also vitriol, bile, and cruel backstabbing). Even if the classroom is extended with virtual environments, you still need the classroom space for the arguments that drive those fields.

A university in space hits the stumbling block of getting all those people up there and into one place, while competing with either the on-line certification programs or the classroom degree programs. A technical school might have a better chance of competing with Earth-based schools (I doubt VR will ever fully substitute for hands-on technical apprenticeship. For one thing, the VR system will probably be set up to avoid cutting off a student's finger as an object lesson), but would require a stable or growing population of young people. Schools may turn out to be one of the last things built in space.


Rick said...

True, universities are evolving under both economic and technological influences.

It will be a long time before we have freshman dorms up there, if freshman dorms still exist. What I vaguely have in mind is a postgraduate research center. But like so many things it is predicated on being able to put people into orbit for a non-exorbitant cost.

Jean-Remy said...

I don't think the cost of launching people into space is that much of a hindrance. For whatever reason, be it Cold War rivalry or international scientific cooperation, the fact is there's been a steady increase in the number of people we put in orbit. We started with one-man capsules on suborbital hops. In 60 years we've arrived at roughly half a dozen people in orbit almost constantly since Mir, and continuing with the ISS, which after ten years is still being expanded. Since the Cold War excuse of strutting our stuff through impressive gestures is gone, then why are we still doing it? It is obvious that there is something of value in having a permanent, manned outpost in Earth orbit, despite the staggering cost.

Why? Let's come down to Earth for the answer. The amount of money funneled into high profile research is enormous. Every technologically advanced country boasts particle accelerators, high energy laser labs, magnetic and inertial confinement fusion research reactors, massive optical and millimetric telescopes and arrays built in remote areas... the list goes on. In terms of costs, experiments like the LHC alone show that we're willing to spend those staggering amounts of money on science.

And why should we not? Time and time again the returns are discoveries that change our lives. All these facilities have evolved from Menlo Park: while Edison didn't actually invent the lightbulb, he manufactured a type of lightbulb that was actually practical. Can we envision modern life without the lightbulb? It's impossible. In light (pun absolutely intended) of this development, who doesn't want to invent the new lightbulb? The costs are staggering, yes, but the returns are not any less so. A world without Velcro? Hard to imagine now, isn't it?

The ISS is a research center, a "University" in its old definition: an conglomeration of intellectuals gathered to facilitate an exchange of ideas. The men going into orbit are no longer the fighter jocks who had the "Right Stuff": there are more doctorates in orbit than there are in some universities on the ground. In the space (another lame pun?) of a few decades, the conquest of space has changed from a politically motivated saber-rattling to a genuine effort at understanding what our capabilities are.

After all, that's the idea behind being there at all right now. If full-scale use of space weren't the intended goal, then it simply would not happen. Industrializing LEO is an implied goal of our research. We do not research just because we feel like it. Not at those price tags! Nowadays there is no such thing as pure research: it as all toward a desire to apply knowledge to further our lives.

While we can speculate as to how fast it will happen, unless we managed to obliterate ourselves in an orgy of willful or neglectful annihilation, the exploitation of space, of the Moon, perhaps beyond, is a given. The cycle of Exploration, Expansion, Exploitation is not just a major recurring theme for humanity, it is arguably our very nature.

Of course I am preaching to the choir. None of us would be posting on this blog if this wasn't the future we all envision.

As a more practical approach to the matter at hand, I think we already have our university in space: a government-funded ivory tower for doctorate holders. Is it a surprise that the first civilians invited to fly into space have been teachers? The next step? I think within the next 50 years will see the birth of a new Silicon Valley in LEO. From there, actual robotic mass-production facilities. The cost of reaching LEO will drop not just because of new technologies, but simply because of increased frequency. The more flights, the cheaper the ticket.

Rick said...

I pretty much agree, but I'll take it up in the 'Sunday Reading' comments!

Anonymous said...

Jean: "The ISS is a research center, a "University" in its old definition"

The old definition of 'university' is 'school', not 'research lab'. The idea of universities as a centre of research and development is very recent.

Other than that historical quibble, I agree with the majority of your points. Particularly the point about launch-costs not being as severe a bottleneck as launch-tech salespeople would have us believe (If we really wanted to get launch-costs down, the Black Arrow or Scout family of rockets could be built in well-equipped garages). At this point the launch-cost problem just sets the ratio of meat-units to machine-units in space.


Jean-Remy said...

I was referring (imprecisely) to the way universities got their start, from the meetings of philosophers in Greek Agoras and Roman Forums. Although their main incentive was to gather as thinkers and philosophers, so many students, prospective students and crowds of simple passerby's joined in that they became more than simply a forum for discussion (hence the origin of that particular term) and became centers of learning, from which Universities evolved as a way to formalize and institutionalize the practice. Yes Universities were built to be schools, but the main method of attracting teachers was to offer a place where academics could congregate with their peers and exchange ideas. Universities aren't schools that evolved into research centers, they were research centers that gathered students. The University of Constantinople founded in AD 425 was meant from the beginning to be not only an educational center, but a center for research and academic independence.

Anonymous said...

Runs out, plants flag "I claim this comments thread in the name of an academic debate regarding early medieval Scholastic dialogue versus the post-Englightenment view of research and development!"

Hm. Tempting, but maybe not.

Rick: "Over decades a boneyard of old structures and equipment will accumulate, begging to be repurposed. Orbital (or lunar, etc.) machine shops will appear to do this work."

The junkyard idea is neglected in SF, probably because the early field was dominated by techies rather than historians. In the real history of colonization, more early colonies failed than not. The successful colonies sometimes stripped the old outposts for worked materials, but the truly valuable resources left by the failed colonies was experience. Once you know what not to do in space, you can repurpose the scrap left behind by the first generation.

I can imagine some old-timer boring kids about how they tried to build habitats in S-type asteroids, but the adhesives used to attach to the surface would degrade the silicates, and kids these days have it soft living in their ceramic-sealed M-type asteroid hives...


Rick said...

Jean - On the history of universities, a quibble that they do not derive from classical quasi precursors, but evolved on their own around the 12th century. I'm not sure how much impact Islamic examples had, though surely some.

That said, my impression is that faculties and students coalesced together, and mainly did not grow out of earlier monastic or cathedral schools.

Faculties and advanced students go naturally hand in hand - researchers need underpaid grad students, and the grad students need expert instruction (and letters of recommendation).

In space I'll agree that a research center is likely to come first, taking on other university functions as it grows and the cost of going up there falls.

Ian - I thought of the boneyard mainly by reference to naval hulks and the old rolling stock you see around railroad stations.

You're probably right about why junk is under-used in SF. I don't even recall many references to 'old town' sections in large space stations.

Jean-Remy said...

I would just contend That universities appeared in their current form once societies regained stability after the collapse of Rome brought about an era of religious control over information. Sure the "Dark Ages" were probably not as dark as we usually think, but there is quite a bit of evidence of information suppression in that era, notably the fire of the Great Library of Alexandria, which happened during a religiously-motivated riot. The repression of Galileo is a pretty good example of what can happen when religion controls knowledge, and there is a fine line between preserving knowledge and hiding it in a vault so no one else can get to it.

I don't think anything evolves "independently". Though universities in the 12th century appeared as a new thing, they were merely a new and ingenious way of doing old things.

Going Meta: on the subject of junkyards and boneyards in space, that is really an excellent point. In fact Babylon 5 might be the only TV SF show which actually featured disaffected, undeveloped zones where slums developed on a space station. When junkyards are shown (*gasp* "Soldier") it is usually done completely nonsensically, which doesn't help the reputation of the junkyard for SF writers and audiences. However, I can see the appeal of a Roanoke IN SPACE. On the other hand, the reason we don't know what really happened at Roanoke is because we didn't have the communication abilities we have now. If we lose a colony on the Moon, we'll know right away when the constant telemetry goes out. And when problems develop, there's always home base a phone call away for advice. Like everything else, we can't apply 100% historical ideas to space, mainly because of the lessons that were learned after the incident in question. Still, there's a story there.

And those damn kids really do have it easy with them newfangled torch ships. We used rockets to travel 300,000 miles to Lunar U, even during meteor showers. Up the gravity well. Both ways.

Rick said...

Agree that universities, like other institutions, don't come out of nowhere. The university movement in the medieval West coincided with the rise of Aristotelianism, the 'founding fathers' were surely familiar with the works of Aristotle - or rather, class notes by his students.

I was thinking mainly of the institutional development, where the universities were homegrown, not a direct borrowing. In general, I think that research and advanced instruction are closely related, and more often joined than separated.

Slums are not uncommon in written space SF, but mainly just for the dystopian stylistics, not as components of a social ecosystem.

On Roanoke, part of the appeal of interstellar SF is that it is easy to have FTL ships in a setting without having FTL radio, allowing all the plot lines that depend on outposts NOT being in contact with the home base.

Jean-Remy said...

Slums in SF: I was speaking of the particular case of space stations or remote outposts. In general slums in SF are present "back on Earth" or in older colonies that have been established for a while, but seem to be (mostly) absent on shiny new outposts. I think the closest it gets is in Peter F. Hamilton's Night's Dawn, where old mined-out asteroids are poor and underdeveloped.

On the one hand it seems logical: that shiny new space station was very expensive to build, and whoever owns it wants to keep it shiny and clean to get people to work there.

On the other hand since they are so expensive it is also easy to see a station whose funding got cut and parts of it remain undeveloped, or it had been built bigger than necessary hoping to expand and the expansion didn't happen. Hopeful people coming to work there find themselves laid off when the parent company can't goes bankrupt, they can't afford the trip home, and there's this unused part... which I think was the reasoning behind Downbelow on B5.

B5 was actually a good example of the slum in fact being a part of the social ecosystem: the residents of Downbelow were used as cheap temporary labor force with no legal protection--illegal immigrants, basically. They even were a tourist attraction in some ways, with colorful flea markets and shady casinos.

Rick said...

B5 was well worked out in a lot of ways, one reason it is one of the relatively few sci fi TV shows I actually watched.

My guess is that on the time scale and tech level I'm considering here, 'the midfuture,' true slums in the classical sense probably wouldn't happen. Margins are too small; if a spacehab is in decline, someone will pull the plug on it and decommission it outright.

I do see a sort of demimonde, what I call the shadow side, which will surely find a home in underutilized facilities - the boneyards, and also as you mentioned, expansion facilities not yet (legitimately) filled.

The shadow side is not precisely an underworld, because most of it is not illegal, just unofficial - but as the old timers say, nothing stays in orbit without it.

Space will have weird economics on a human level. Given foreseeable tech, prices will be extremely high by terrestrial standards, because it is either hauled up from Earth or produced in an environment that makes the Gobi Desert look like the Loire valley.

This will produce strange discordances. A working stiff's cafeteria ticket may be worth $1000 to a tourist who wants to scrimp on $3000 restaurant meals.

Not to mention the economics of the oldest profession ...

Karl Sánchez said...

Great post! I am thinking of economics and come to ask
what about china? if the Chinese continue growing at the speed they have, they will need another earth for raw materials to consume in a couple years, then economics has an upper hand, (ok it is probable that you get something like Bender to pick up the iron meteors and haul them to LEO, but then, you will need a redshirt tech to fix the robots before they try to reenact Tunguska)

Jim2B said...

There is actually a middle ground to this argument. Space lift is expensive, just not quite so expensive. However, methods emerge to boot strap space industry without actually having to build infrastructure.

A newer technology development might just fit this need: 3D printing. Refined materials (iron, nickel, aluminum, etc.) go in and a part comes out. We can do this now with metals and plastics. Imagine if we could do so with multiple materials in the same part.

High tech, high volume, and ultra cheap production would remain outside of the near-term space industry capabilities but I can start to envision how moderate investments in space industry could begin to pay back that investment by providing mass intensive lower tech components to LEO for use in other space infrastructure.