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Trick Question

Commenter Heteromeles suggested, with respect to the design of closed-circuit biospheres for long-duration starships:

[This] isn't a design for a livable formerly-known-as-starship. Rather, it's a test to see if the design will work.

Here's the test: the closed ecosystem within the ship has to be able to produce enough beer to satisfy all the beer consumers within the system.

The reason? Beer's pretty central to culture (see How Beer saved the World for a humorous and fairly accurate take on the role of beer in history). If things are so tight that there's not enough acreage to produce alcohol (beer or equivalent), then there's probably not enough surplus capacity within the system to withstand the inevitable problems they'll face. Ditto if everyone has to be sober all the time just to keep the ship running. In the later case, people will distill alcohol anyway, and it will be a problem, rather than a central part of the ecosystem.

Something to think about. If they can't drink, it probably won't fly.

Okay, let's take this test seriously:

What is the minimum number of species necessary in order to produce beer aboard a generation ship?

Note 1: An absolute minimum is compliance with the Reinheitsgebot; however, I'd also like to see analyses for a British bitter, a Belgian Lambic, and (even though I wouldn't be seen dead drinking it) a mass-produced American rice-based 'lager' style beer.

Note 2: This is a trick question; it's not about the specific ingredients that go into the beer, but about the food webs that sustain those crops.

Suggested additional reading: The Makeshift Rocket by Poul Anderson. (Probably not a useful reference, but amusing.)

290 Comments

1:

The book Potato by John Reader was pretty good, and talked about potatoes for space flight. A potato culture and vodka?

Re. biospheres, I really think the bio-domes should have been insulated, underground, with metered energy inputs and lights, rather than crazy variable energy transmission greenhouses ...

2:

Well, what actually makes up good soil is still an area of active research. Although I suppose you'd want to do hydroponics for the actual growing, you're still going to want some kind of mulching process digesting waste.

3:

Potatoes are carnivorous, it appears. (Original paywalled reference.)

This has disturbing implications for their use in closed-circuit biospheres -- are they dependent on micronutrients supplied by [dead] insects, or are they merely a useful adjunct?

4:

Note that beer depends on yeasts, and we need to be careful about radiation exposure of unicellular organisms. I can see there being several yeast strains carried, and each managed as multiple parallel lines, with dried or frozen samples in heavily shielded storage.

5:

"mass-produced American rice-based 'lager' style beer"

My brother likes to refer to these as "industrial lagers".

6:

Well, all right, let's start with the essentials - barley, hops, wheat and yeast. We also require sufficient surplus water for the beer in addition to the water requirements of the plants. The plants themselves would form part of the air renewal system, but don't forget that when plants aren't photosynthesising oxygen, they are respiring themselves and using oxygen so you need enough extra to keep them too.

Next level - soil for the plants to grow in, which is a whole macro-environmental cycle in itself. I have no idea how many interdependent organisms exist in a soil. I do know that it is a dynamic cycle, not just a substrate, and it depends on having insects, fungi, bacteria and worms as parts of the living system. It also depends on having a mineral base and a weather system to keep it turning over.

The soil depends on having several types of plants growing in it at different times, to replenish nitrogen and minerals, and decay organisms to break down organic matter for re-use as compost. Then also our beer plants depend on insects for pollination, which require food plants of their own surplus to our beer requirements. You're going to want to cultivate a bee garden. This has the happy benefit of providing flowers for the expedition members to appreciate while they drink their beer.

And the decay organisms, yeast, insects and food web plants require natural enemies, predators and grazers to keep them in check. You'd probably want to leave behind many of their parasites, bee mites, etc. but you'll need to know which are parasites and which are symbiotes. Those will also require natural enemies. We must presume that cropping is part of the overall system, so the system is not a 'natural' one, but one that has been calculated to remain in balance given the activities of farmers. If a disaster happens to the expedition and there is no-one to make and drink the beer, then the whole system will fail.

Alternatively you could try for hydroponic growing and manual pollination, and cut out a whole lot of that structure, but you'll still need to keep the yeast in check and make sure that whatever you use to provide slurry stays in balance in your organic digester. Plus, who wants to be going round plants pollinating them when you can have bees do it?

7:

The Poul Anderson story was also called: "A bicycle Built for Brew"!

Watch it though, there are also nasty little puritan liars about, like this fake "charity" called Swanswell saying things like:
A society that is free from problem alchohol use altogether
Like Prohibition USA, I presume they mean?

Where do these idiots come from?
And will they PLEASE go back there?

8:

Well, when the temp is >100 degF and humidity 90% you definitely do not want to be drinking "good strong English ale".

9:

Everyone is being remarkably coy about numbers. It's hard to argue Elaine list (#6)... and while there's a fair few unknowns in there, I'd be willing to estimate to an order of magnitude, 10^3.

There are undoubtedly some naughty bits in there not expected though. Commensal bacteria for example. Hard to imagine, even if you have a clean population you won't get some phages and things included. If they all count, up that to 10^4 ±1 order of magnitude - you may not want them all, but I bet they'd be there.

10:

One assumes that aboard a generation ship there is absolutely no reason to run the biosphere at 39 celsius/90% relative humidity, unless the crew want it that way (say, in the sauna). Indeed, it's worth noting that RuBisCO loses efficiency at higher temperatures so running at that level is probably going to be detrimental to your oxygen cycle ... (assuming it relies on plants with unmodified RuBisCO).

11:

Good starting point! Hmm. One wonders how many random organisms one can find in, say, one gram of randomly-selected garden soil?

12:

One of Bob Shaw's Serious Scientific Lectures addressed the idea of beer in space in part to solve the propellant mass problem. He started from the empirically derived truth that when you drink a pint of beer you always excrete more than a pint of fluid afterwards.

Bob's genius was to posit a closed-cycle beermaking plant on board a spaceship plus a crew of hardened drinkers with osmium-lined kidneys. The crew would drink the beer and the "waste" would be cleaned up and put back into the beer-maker. The excess fluid would be either used as propellant or if the tech was up to it consumed in a matter-energy plant of some description. He closed with the terrible scenario of the captain ordering "full speed ahead!"...

The prototype ship was called the "Yurin 8" as I recall.

13:

Barley isn't pollinated by insects. Neither is wheat. The hops, of course...

14:

Wait a sec. Beer, while delicious, is a normally a high carb food, and carb-laden diets degrade immune function and cause diseases of aging.

Even if you want to stick with beer, adhering to Reinheitsgebot might not be a good precedent - it's the western world's first drug control law!

Suggested Reading

Sacred and Herbal Healing Beers: The Secrets of Ancient Fermentation by Stephen Harrod Buhner (1998)

Aging research by Cynthia Kenyon at UCSF

15:

I think this is a secondary consideration, but what would be the best way to sanitize our brewing equipment?

-Would we eventually run out of bleach? (How do they make bleach, anyway?) Is bleach too dangerous to risk getting into a closed ecosystem?
-Or could we just dangle the equipment over the side in a net to be sterilized by the engine exhaust?
-A UV radiation autoclave?
-A regular autoclave?

16:

Why beer? Let's not use a sensationalist "documentary" as the support for requiring "beer" for human living. More than likely, any alcoholic beverage was useful, and this was primarily to ensure safe water for consumption (c.f. "The Ghost Map" about cholera in C19th London). Michael Pollan makes the same case for cider in the early USA -"The Botany of Desire").
So we can probably go with any alcoholic drink to satisfy water consumption safety [on a starship/space colony?!?] and partying - beer, cider, wine, vodka...

Essential fermentation organism - yeast. Well we know that we can grow yeast easily and sustainably effectively indefinitely in simple bio reactors. The variant might be difficult - the famous SF sourdough bread cannot be made anywhere else apparently, but that isn't a requirement for yeast generally.

We can make alcohol with just plain glucose (not sucrose) as a source, if the yeast doesn't have to grow, just ferment the carbohydrate to ethanol.

Glucose is the primary product of photosynthesis, i.e. can be made by algae, such as Chlorella. Again, we can grow Chlorella is very simple artificial conditions, requiring no special food webs, just physical/chemical recycliny of organic materials.

Bottom line, we can probably satisfy the social requirement for alcohol with minimally just an alga and a yeast.

Which really capitulates what the original space colony folks believed, that complex ecologies are not required for space colonies, even if they are desirable. Brute force energy usage is a substitute - and who thinks that a star ship/space colony will not be an energy rich environment?

So if you want a test to require complex ecologies that can sustain themselves in space without lots of technological support, well that's OK, but it is a rigged test. It is a steam punk thought experiment.

That isn't to say that vintage 1970's space colonies with Californian or Hawaiian ecologies aren't attractive, but simply that they are not necessary and that the way to go is to think in terms of simplified biology, probably engineered. The colony will look much more like a city, with factories, not farms producing the food and other life support. Plants will be more decorative than functional, just as they are in the glass atriums of showcase architecture.

17:

Alex beat me to it: beer, much though I love it, seems like a pretty unnecessarily over-engineered solution to the alcohol/intoxicant problem. You will be wanting vodka for this job, I think. Solve the problem of growing wheat ("...and then a miracle occurs..."), and then you basically just need the extra space and energy to run a pot still or ten. Plus, as a bonus, the intoxicant you've produced can do double-duty as a rather useful solvent and antiseptic. Space is no place for single-taskers.

18:

(Or rather I should say "solve the problem of growing just about any plant, and then keeping yeasts alive in space", with same caveats about miracles...)

19:

It's a good question, in both general and specific terms, but in all seriousness I would go a step further. Beer is your first test, and a good one, but I wouldn't risk my life on a generation ship that couldn't produce a proper gourmet meal - anything I'd want to order off a decently-sized menu - out of the following materials: regolith, water and bacteria.

That's what the mature technology looks like; open asteroid, insert France.

20:

Wait a sec. Beer, while delicious, is a normally a high carb food, and carb-laden diets degrade immune function and cause diseases of aging.

YELLOW CARD -- this thread is not intended to host a diet war! Especially the calorie-restruction stuff (which I suspect is confusing correlation with causation).

(The amount of carbs you can get from beer is in any case fairly limited -- you'd need to drink several pints every day to have a significant nutritional effect.)

21:

You're missing the point -- which is to provide a starting point for analysing the number of supporting organisms required for the basic cohort required as inputs to one particular food product.

(Leaving aside the issue that for many folks, a single choice of intoxicant -- which happens to be dilute industrial alcohol -- isn't exactly fun, and they and their children are, in this scenario, doomed to be vodka-heads for life.)

Also: my take on the generation ship is that they can't afford to risk reliance on a single process that is required for multiple functions -- redundant systems are vital.

22:

Also: my take on the generation ship is that they can't afford to risk reliance on a single process that is required for multiple functions -- redundant systems are vital.

The key word is reliance. I would suspect that you would want multiple functions from each process, but also multiple processes for each function.

Going almost back on topic... will their be sufficient sand taken on board to make sufficient beer glasses for all this produce to be consumed?

Going slightly more back on topic... Whatever number of species you end up with, I would recommend at least taking 3 varieties of each. Simply to allow for a little resilience in case of having a variety which was particular vulnerable to an unplanned pest or blight and was completely wiped out, taking the beer with it.

23:

don't forget that when plants aren't photosynthesising oxygen, they are respiring themselves and using oxygen so you need enough extra to keep them too.

Not usually a problem, since when that happens, the plants are actually shrinking, and they try to avoid that. The old thing of taking flowers out of hospital rooms at night was based on a total failure to actually consider orders of magnitude - there's no way plants compete with warm-blooded mammals as oxygen consumers.

24:

While I disagree with the idea that it's desirable for a workforce to be intoxicated with recreational depressants in principle, a generation ship's capacity to handle several generations worth of an ecosystem is probably best represented by its capacity to produce a wide variety of fermented foodstuffs. I don't think it's reasonable to stop at beer, if we are betting the lives of quite a few humans on the sustainability here. However, if a generation ship can produce several varieties of beer, wine, and kimchi, and can also produce yoghurt, I'd feel a lot safer living there than if it could just produce beer.

25:

This is about science, not woowoo or crank diets.

26:

No, I totally get it. We obviously need hundreds, maybe thousands of organisms to get us from regolith to soil that can support hops, and possibly an additional set of hundreds or thousands of organisms to get barley out of our regolith. We don't know exactly what those organisms are, or how they work, and we need to do research on this before we build our starship. I get that the ability to produce surplus goods for the making of beer is a good first test that we understand the dynamics of ecosystems. I totally get all of that.

But before I get on a starship and commit all my descendants to this crazy, dangerous idea of colonizing another world, I want to see a lot more surplus goods than just beer.

27:

Going almost back on topic... will their be sufficient sand taken on board to make sufficient beer glasses for all this produce to be consumed?

What's wrong with pewter tankards? Or disposable cups made out of cellulose? (Okay, the latter wouldn't taste good. But beer and pewter go together just fine.)

Actually, sand -- silica -- may well be something a generation ship has a surplus of; think in terms of radiation shielding and structural mass for buildings, and just try to remember "it's not a ship, it's a city state with an engine".

28:

While I disagree with the idea that it's desirable for a workforce to be intoxicated with recreational depressants in principle,

It's not a "work force", it's a population of citizens. Probably only 10-30% of them are part of the actual "work force" at any given time, insofar as there will be children and old folks and -- because humans breed back towards the mean -- plenty who may be willing and of an age to work but not able to contribute productively to a high-tech interstellar civilization. (I'm going to nail my euro-socialist colours to the mast right now and say at this point that throwing them out of the airlock is not an appropriate way to deal with this problem; whereas there will be plenty of opportunities for arts'n'crafts or sports activities to enrich the cultural life of the society.)

29:

Uh, actually looking at their website, I don't see anything about Prohibition. They advise against drinking too much, e.g. binge drinking, or drinking every day.

30:

Continuing with the thought on biotech. What are the flavor elements of beer? Can they be engineered into other organisms, extracted and added to a "synthetic beer" beverage? Must we have those waving fields of amber grain (and hops) in the colony, or could the essential "beerness" of beer to factory produced? We cannot do this today very satisfactorily, but after a century of advanced biotech? Oenophiles would say that this is sacrilege, but the possibility of manufacturing wines is very real. It is about perception, rather than capability.

Perhaps we need a Parker Test for synthetic wines, and the equivalent for beers?

31:

How many species for a proper range of intoxicants? Cannabis, shrooms or peyote (though synthesized LSD seems to work fine), opium, coffee, chocolate, qat and coca if you're being multi-cultural?

32:

If you've got rye, taking along some ergot spores gets you lysergic acid (from which it is a hop and a skip to LSD-25). You also get ergometrine and ergotamine, which have their own uses (inducing labour and dealing with migraines), although they're unfashionable pharmaceuticals these days.

Cannabis sativa is generally useful (for hemp as well as hash), and papaver somniferum is an analgesic wonder drug (and a hop and a skip from morphine to diacetyl morphine if you want a really good anxiolytic/coronary vasodilator/analegesic for handling infarctions, not to mention a very nice narcotic). I'd be inclined to leave coca behind -- intoxicants that make people sleepy or happy are one thing, but cocaine tends to generate assholes, which would be a liability aboard a generation ship. Cocoa and coffee and tea would all, I think, be useful to have along -- but they're not exactly efficient in terms of their requirement for growing space. Shouldn't forget tobacco, either, but in general I think smoking would be a bad habit to bring along -- chewing tobacco, maybe?

33:

Must we have those waving fields of amber grain (and hops) in the colony, or could the essential "beerness" of beer to factory produced?

BURN THE HERETIC!!!!1!!!!!

34:

To simplify existing growth systems. Horticulturalists have been growing plant tissue, seeds and root stocks under sterile conditions for over half a century. Even whole plants, such as oats.

Why should we assume that a space colony cannot use sterile growing conditions for plants where the biology is not easily replaceable? Maintaining sterile conditions may be hard, but they have plenty of energy at their disposal.

Complex systems may be fashionable to study, but are they a necessity to achieve the goal of long duration, isolated support systems for biology?

35:

Which is why I propose a blind tasting test. It may be sacrilegious to manufacture beer for the religiously inclined, but if you cannot tell the difference from the "hand crafted" traditional item? Do I detect some Ludditism here?

36:

Why is there so little mention of the Biosphere project in these discussions? It's the only actual experiment to date that is relevant. If people are interested in this kind of starship then pumping money into followups is the most viable thing that could be done *now*.

37:

You detect somebody who actually likes the complexity of flavour and texture of cask-conditioned real ale, as opposed to the pale fizz commonly marketed as "beer" by the large manufacturers.

38:

Wow, thanks for featuring this, Charlie!

I've got to underscore the point that this is really about surplus capacity and social resilience. I picked beer (in the broadest sense--simple alcohol fermented from a carb source) because the resources to make it can also be turned into food very easily. If we're growing grain, we can also use the grain for bread, porridge, potage, or barley tea (which is common in Korean cuisine). Ditto with potatoes, although potato beer tastes horrible.

I also picked on it because a certain portion of most populations will make alcohol out of whatever is available. The US ran a great social experiment about 90 years ago that showed how difficult it is to suppress alcohol production and consumption, so I think it's better to build alcohol into the system. Yes, you're going to have to deal with drunkenness in space, regardless. How do you do it?

I agree with those who say that there are other fermented products and other alcoholic drinks. You're absolutely right. Just remember, each of these products requires another support system. If you want yogurt, you've got to have at least goats or soy. Kimchi requires garlic and cabbages, and so forth.

Otherwise, I don't have the numbers. Yet. For those who are interested, I'd suggest looking at how much land is required to produce a given volume of beer (with or without hops), and how much bread that land would produce. That's one way to start getting a handle on the amount of surplus capacity you need in the system.

Similarly, what are good ways to deal with drunks on a ship or in a small, isolated village? This is where the historians among us may have useful information.

39:

(The amount of carbs you can get from beer is in any case fairly limited -- you'd need to drink several pints every day to have a significant nutritional effect.)

Wait, why wouldn't you want to drink several pints a day?

40:

I'd also add that the bare minimum you need for alcohol production is a grain, yeast, and water. That's assuming hydroponic (or aeroponic) grain growth, and some mechanical/chemical means for breaking down organic wastes into the nutrient solutions needed to grow the plants.

That's the simplest system, but I'm doubt it's the most efficient or most resilient system. Biological systems are arguably more resilient and energy efficient, but they are slow, and processing speed affects the size of the systems. Moreover, Biosphere 2 demonstrated that uncritically shoving organic agriculture into a closed system causes problems.

Also, as noted above, grain is wind pollinated (fun for the ship's ventilation system--many people are allergic to grass pollen), so you don't need bees for beer.

41:

With respect, you are not paying attention to what I said. I agree with you that we cannot manufacture quality synthetic beer TODAY. But 100 years from now, when the space colony tests can be underway and preparing for a possible star flight after that? Do you really believe that we will still have to brew beer the traditional way to get a high quality product? If you do, you are positing some sort of magic pixie dust ingredient/process that is not subject to duplication.

42:

The ability to tell the difference is probably linked to survival via better olfactory senses. I'm not a beer drinker, but I can definitely tell the difference between two different varieties of coffee, for example, or two different types of tea. Thus I'm a better pick to survive in the wilds of a new planet than someone who cannot.

43:
And the decay organisms, yeast, insects and food web plants require natural enemies, predators and grazers to keep them in check. You'd probably want to leave behind many of their parasites, bee mites, etc. but you'll need to know which are parasites and which are symbiotes. Those will also require natural enemies. We must presume that cropping is part of the overall system, so the system is not a 'natural' one, but one that has been calculated to remain in balance given the activities of farmers.

May I suggest that the system be large enough that composting be the natural choice returning reworked molecules back into the ecology from the bottom?

Funny thing that; it's been around for thousands of years, but composting as a natural way of righting nutrient imbalances seems to be massively downplayed. Not hi-tech enough, I guess. Or it doesn't sell enough fertilizer.

44:

"...assuming hydroponic (or aeroponic) grain growth, and some mechanical/chemical means for breaking down organic wastes into the nutrient solutions needed to grow the plants.

That's the simplest system, but I'm doubt it's the most efficient or most resilient system. Biological systems are arguably more resilient and energy efficient..."

It depends on what you mean by efficient and resilient.

Biological primary productivity efficiency is generally very low. The main value is that a vast suite of compounds are created that would be hard, and in some cases impossible, to manufacture by synthetic means.

Resiliency is an issue if you want a system that is self-regulating. With abundant energy, this is not necessary. Farming is just such an example, and is far more efficient at producing food we want than trying to harvest an ecosystem that is at a climax.

45:
Ditto with potatoes, although potato beer tastes horrible.

But if you're a spacer, that's what you drink - and you like it. It's even marketed to the tourists: "Drink Iron City Beer!"

May I suggest another likely candidate for this kind of experiment: chocolate?

46:

Chocolate probably wouldn't work. Yes, I share your pain. Here are the problems.

--it's a tropical tree, and chocolate comes from the beans of the fruit. It will take a while to get going, and there's a lot of sunk carbon (the wood in the tree) that you can't use for anything else unless you burn the wood.
--you need to multiply process the beans (including fermenting them) before they're edible. Yes, the pulp is edible, so it's not a unitasker, but in general it's a lot of input (on an elemental basis) for a small output (the seeds), so it's not a great idea for a weight-limited system.

47:

In this case, resilience means that it's hard to take the system entirely off line, and easy to rebuild it.

Basically, you need something that looks a refinery. Hauling out my old copy of Heppenheimer's Colonies in Space, they were pitching a wet Zimmermann process, where you basically incinerate the wastes (high pressure, high heat, with oxygen) down to their elemental constituents, so you've got ash with insoluble nutrients, and effluent with the soluble nutrients. You've then got to refine these two down to get the stuff you need for agriculture. Since I've done a little bit of hydroponics, I'd say that fertilizer formulas are pretty precise, so there's a lot of chemistry involved in going from waste to growth medium.

On a ship, you'll need at least 2 (or more likely 10) of these Zimmerman waste reactors, because anything that works with high heat and pressure is going to need regular maintenance (meaning spare parts, down time, trained mechanics, and the like). That's why I'm not so sure this system is highly resilient. It also takes a lot of energy to run (high pressure, high temperature)

Conversely, hot composting simply requires two cubic meters of organic waste of the right types, but it's slow: you get soil in 16 days. A goat will produce fertilizer in under a day from the right type of organic waste, as will a chicken (or termites and crickets, for that matter). They aren't incredibly resilient, but you can eat them or their milk/egg/surplus insects, so there's a useful byproduct there. These systems are also self-perpetuating (within limits) and self-repairing (within limits), unlike the reactor. If you use a mechanical recycler, you need to be able to build recyclers within your ship, so that's a different set of capacities.

My point is that you grow beer with grain, yeast and a mechanical recycler, so that's the absolute minimum. If you want hops, goat milk, chicken eggs, or whatever, you can certainly do that instead, but it's a different system, it processes at a different rate, and it has different strengths and vulnerabilities. At this point, I don't know which one's better.

48:

Similarly, what are good ways to deal with drunks on a ship or in a small, isolated village? This is where the historians among us may have useful information.

You are familiar with the traditions of the Royal Navy in Lord Nelson's day, I take it?

Two factoids spring to mind: (a) the daily rum ration was half a pint per sailor, and (b) the punishment for being drunk on duty was to be flogged.

Cirrhosis of the liver killed more sailors than enemy action ...

(NB: the rum was usually served mixed with water; and the definition of "drunk on duty" was "lying insensible and unable to get up when ordered to do so three times by a superior officer".)

49:

Trying to maintain a sterile environment strikes me as a lot of work on a hiding to nothing. I suspect the law or requisite variety could be put into service to determine a theoretical minimum and that the practical minimum would be a couple of orders of magnitude higher. However, to find actual viable ecologies empirical research seems a better bet.
The starting point has got to be a sustainable ecology of bacteria and yeasts - take wide sample of gut flora, soil samples from different classes of arable land, from forests - rain, dry and temperate create a 100 bends and grow each one in suitably isolated conditions. Select and mix using, stability, soil fertility and mammal breathable gas composition as a fitness criteria.
I reckon it is a fair bet that a suitable motivate research team could come up with a combination that also generated lakes of best bitter the regular syphoning of which would stimulate more production.

50:

Not directly an answer to your question, but according to the Australian Dept. of Agriculture, there are estimated to be 60k different species in soil.

No idea how many of those are needed for all different types and requirements of soil, but of the order of 10^5 organisms should give you a number of fairly diverse biological systems for beer, whiskey, honey and more.

51:

make that 10^5 species.

52:

"..generated lakes of best bitter the regular syphoning of which would stimulate more production.."

Now that seems like a worthy biotech goal. :)

53:

Doesn't even have to be historical. A while ago I was at a talk given by an ex-commander of a RN nuclear submarine. The audience was somewhat surprised to learn that our nuclear subs are not dry - a drink or two (in moderation needless to say) after a shift is allowed. He explained that after reaching port after weeks or months of isolation, their American counterparts would hit the bars with a vengence, and the next morning would have to be retrieved considerably the worse for wear from under tables/down alleys all over town. He proudly added that our chaps, on the other hand, had to be tracked down in the bedrooms of local womenfolk...

54:

Do you really believe that we will still have to brew beer the traditional way to get a high quality product?

Given the insanely large number of strange organic compounds that lend their flavour and aroma to the basics (hint: you might want to read up on hops), my guess is that it might be possible to manufacture something that tastes arbitrarily similar to beer, but brewing it the old fashioned way may well be the most efficient way of producing it. Note that there exist some very interesting automatic gadgets you can buy in home brew shops today that will take you almost all the way to finished beer with inputs solely of malt, water, wheat, hops, and yeast. If you need a closed-circuit biosphere to provide oxygen and food for your colonists ...

55:

An interesting point is that breweries recycle their by-products; malt and grain from the sparging process goes as animal feed (pigs or goats or similar), while surplus yeast (from bottom-fermenting strains) can be lysed in strong brine and used to make marmite or vegemite (dietary supplements high in B vitamins).

56:

He weighs the same as a duck, then?

57:
Chocolate probably wouldn't work. Yes, I share your pain. Here are the problems.

--it's a tropical tree, and chocolate comes from the beans of the fruit. It will take a while to get going, and there's a lot of sunk carbon (the wood in the tree) that you can't use for anything else unless you burn the wood.

--you need to multiply process the beans (including fermenting them) before they're edible. Yes, the pulp is edible, so it's not a unitasker, but in general it's a lot of input (on an elemental basis) for a small output (the seeds), so it's not a great idea for a weight-limited system.

Ah, I see I was being to elliptical . . . my point was - per Charlie's "hundreds of millions" needed for a viable interstellar mission - that an ecosystem having enough give to produce excess beer might not be large enough to last the 500 or 1,000 years needed to reach a target, and if necessary, return.

59:

If the emphasis of the question is shifted just slightly, might mead not be a more sensible alternative to beer? Given that the principal ingredients are honey, water and yeast, the number of species involved is just two. Also, though the keeping of bees may present other problems, they (a) solve the pollination problem for other crops, and (b) produce honey that is useful on its own account, independently of its use for making mead.

Finally, mead has been a staple of Indo-European myth since all the way back. In fact, the anthropologist Claude Lévi-Strauss suggests that the manufacture of mead enacts the movement from nature to culture by taking a good from a celestial agent (the bees) and humanising it. (Think Prometheus, but in relation to booze.)

If quasi-religious must be had (and the evidence suggests they'll emerge spontaneously anyway), then surely mead would be the proper drink for our cosmic pioneers?

60:

All you need is E.coli, S. cerevisiae and lots of plasmids.

61:

Regarding the question of what it takes to make bleach, it's possible to make bleach with just salt, water, and electrolysis via the chloralkali process (wiki). It's energy intensive, but on the scale of a space colony, bleach is a pretty easy problem to solve.

62:

"...my guess is that it might be possible to manufacture something that tastes arbitrarily similar to beer, but brewing it the old fashioned way may well be the most efficient way of producing it. ...[]...If you need a closed-circuit biosphere to provide oxygen and food for your colonists...

If at some point you can create beer without traditional plants/farming methods/brew processes, then that starts to undermine the rationale behind the thought experiment, i.e. that you need a large biology for a space colony/star ship.

It may be cheaper to do it the traditional way, on earth, but perhaps not in a mass/space limited environment. If you can accept that for beer, or wine, then you can consider that it is possible for other foods too. Algae based steaks - indistinguishable from steers.

I don't mean to make biotech the magic wand that solves all spaceflight life systems problems, but given the rapid advance in techniques and knowledge in the biology space, unless we run into some fundamental constraints, we have to consider that traditional food sources will change on earth, and even more radically in space, as they are coupled with different recycling systems.

For space colonies in the solar system, complex hi-tech may be fine, as there will always be a large, technological economic system to support it. This probably will not be the case for a star ship, which might mean that biology might be a better way to go (c.f. Joan's question for a biological ship) and your own apparent predilection for Elysian fields within the hull.

63:

Further to Eloise's answer, this 2007 paper, co-authored by scientists in an assortment of (north and south) American countries, suggests about 25,000 to 50,000 different species in a gram of soil. Of course, that's just bacteria, and samples from different sites didn't contain the same species. (Indeed, there look to be some very substantial, not to mention important, differences between bacterial populations in different ecosystems:


the bacterial diversity of the forest soil was phylum rich compared to the agricultural soils, which are species rich but phylum poor. The forest site also showed far less diversity of the Archaea with only 0.009% of all sequences from that site being from this group as opposed to 4%–12% of the sequences from the three agricultural sites.

Such differences may well prove significant when trying to set up sustainable self-contained habitats.)

64:

This is offwandering off topic, but given the requirement for producing malt, I'm tickled by the idea of a colony traversing the cosmos smelling like the West side of Edinburgh on a brewing day...

65:

While I have the ear of biologists and people interested in starship biology...

Is it at all feasible to turn chemotrophic organisms into something humans can eat? How many steps would it take and how much embedded energy loss would it entail? I ask because photosynthesis is an extremely energy-intensive way to make food if light isn't free, and between the stars you will have to provide your own light. Electrochemical reduction or oxidation of substrates can couple electrical energy to organisms much more efficiently than artificial illumination. But if the things that humans can eat are several steps removed from the chemotrophs the overall efficiency may be no better.

If you do stick with photosynthesis, how much light per passenger does it take to satisfy their food inputs? How many watts of primary energy to produce the light? Can we keep the asteroid city-ship interior livably cool, given the high volume-to-surface-area ratio of a roughly spheroidal vessel?

66:

Have you read Kage Baker's Empress of Mars?

67:

Given passing comments in SF stories I have encountered over the years and a friend who has worked on submarines in the past; I have always assumed that any space vessel would smell incredibly ripe to to anyone encountering its interior, save for its inhabitants who would be long inured, desensitised even, to the myriad aromas present.

68:

heteromeles @ 38
If without HOPS, it isn't BEER it's ALE.
BEER requires H. lupulus to make it beer, by modern definitions, at any rate.

Others.
Yes,
The number of organisms in SOIL is scary, and we would probably need at least 80% of them .....
The interlocking/interplay of such complex micro-ecosystyems is only now being partially understood.

SoV @ 43
Composting.
Well, ask any well-educated holder of an allotment about that one.
"Turn it over, plough it in, dump it on"
It's amazing how productive an apparently baked-clay plot can become, with the addition of a few loads of (council-supplied) part-roasted black-gunge-compost ......

Soil chemistry and inter-acting syatems is/are difficult.
More than that, at this late hour, this deponent is not saying

69:

So if the ship runs out of beer do the crew fall into fey moods and lock themselves in their quarters, manufacturing exotic items or going on murderous rampages?

(This starship is reminding me more and more of dwarf fortress...)

70:

Why are people worried about mass constraints?

Given the risks and uncertainties of this kind of venture it would seem wise to take a lot more mass than the minimum necessary -- three orders of magnitude more, at least. (Re-read Charlie's "The High Frontier, Redux" for a refresher on a few of the issues, if you need to.)

And mass is relatively cheap. Remember that kinetic energy scales only linearly with mass, but with the square of velocity.

So to me the trick of the question is that it doesn't matter. A starship with any chance of success will have room for several million species.

71:

"When we reach the ethanol cloud, we can STOP DRINKING THIS SHIT!"

Dirk@8: what you need is a good IPA...not the superstrength American kind, either. Marstons' Old Empire is recommended and comes with a sailing ship on the label for relevance.

72:

Spiedel's Braumeister - eh, the Germans. I was not so long ago in a brew-pub in Berlin with a huge copper fermentation vessel. I was wondering if it was just for show, when I noticed various sensors and electronic controls hooked up to it. Trust the Germans to love traditional brewing so much they automated it.

73:
I'm going to nail my euro-socialist colours to the mast right now and say at this point that throwing them out of the airlock is not an appropriate way to deal with this problem

This raises a related point, which is that throwing them out the airlock would be an appalling waste of biomass. This is a more relevant problem than it sounds: assuming that we're dealing with a closed system, the largest amount of biological material in it by weight is going to be the beer-drinking meat sacks. It could not plausibly survive more than a handful of generations without all that mass being recycled back into the system. That means we need more than just a soil cycle: we need to be able to recycle large mammals.

Culturally, people would just have to get over it.

74:

Typically, plasmids need some sort of selective marker (usually antibiotics) to maintain them. Run out of antibiotics & the plasmids are eventually lost becaus carrying the plasmids comes at a fitness cost.

So you either have to have the microbiological capability to support them, or go the other way & you're looking at chemists if you want to synthesize your beer. They come with different failure modes.

75:

Speaking as someone who's done a bit of soil science (counting mycorrhizal fungi), I can tell you that it was routine to find organisms in wild soil that we couldn't even identify to kingdom. Everyone who did that work had such specimens. One of the professors I worked with did early work on soil bacterial diversity, so those counts are right.

The soil biologists are fond of noting that we're standing on the next biological frontier. Apparently, that's too boring, which is why biotech scientists are spending more time working in the deep ocean.

As for how much of this matters in a starship, the answer is we don't know in general or particular. Plant dump up to 20% of their total photosynthate into soil and soil organisms, and the high-carb zone around roots (the rhizosphere) has a very different organismal community than soil without plant roots. It's likely that the rhizosphere community is crudely analogous to our gut community, in that the organisms in it help plants take up nutrients. Conversely, plants can live without a rhizosphere (as in aeroponics), just as we can live without gut bacteria: for a fairly limited time, imperfectly, with other problems cropping up.

It would be nice to get NASA to do some soil experiments on the space station. Designing a small system that is complex enough to be realistic, yet small enough to learn something from it, is a non-trivial design exercise.

76:

The feedstock production is far more efficient for single-cell systems such as Chlorella or Spirulina. Furthermore the protein content would be higher for these than for soil-based plants. Microbes would grow fine in zero-g, although they may be more antibiotic-resistant.

Won't we also be recycling everything? Human dander and skin flakes would add even more protein.

77:

I'm more a yeast person, but yes, there's a lot down there we know very little about. Traditional sampling only is able to recover organisms that are culturable & depending on whose figures you look at, that might be only 10% of what's out there.

Next generation sequencing approaches are revealing some of these previously un-documented species, but that just leads to more questions: if we can't even grow them in the lab, how do we study them?

78:

Harness the power of dust mites?

79:

It's also worth noting that most Australian soils are rather depleted and low in nutrients, and need regular applications of fertilisers in order to yield crops (it's one of the main inputs for our farming sector). Sustainable farming here in Australia tends to rely very much on building up the soil, which often means importing an entire biosphere into a small area in order to be able to sustain growth (one generally built around the waste products of imported European livestock).

80:

In a pinch, a very vile pinch, there's prison hooch.

http://www.blacktable.com/gillin030901.htm

This particular recipe requires oranges, ketchup, sugar, and a can of fruit cocktail, though it can be made from all sorts of things. The folks who tried it describe the taste as "bile flavored wine cooler".

81:

"It would be nice to get NASA to do some soil experiments on the space station. Designing a small system that is complex enough to be realistic, yet small enough to learn something from it, is a non-trivial design exercise."

It would be simpler to test a sterile system, although the control will be difficult to construct. Perhaps the sterile system could be a control in the soil experiment?

I'm more sympathetic to simpler, micro organism approaches that are engineered (or post processed) to create a large variety of foods. If the crew end up with Soylent Red/Yellow like food, then that might be acceptable. After all we eat a lot of processed food today, so it must be popular, even if not particularly healthy. It will also be a lot easier to control vats of organisms and the short growth cycles mean lower mass and less risk of food shortages if a "harvest" fails.

82:

While mead is much simpler than beer, I will note that our host specified beer.

Mead is simpler than beer, and might provide a good base-case for fermentation in space.

At least, a better base case than prison hooch.

83:

The thing about beer, once again, is that, in case of emergencies, you can eat it without fermentation.

Mead requires honey, which requires bees, and a source of sugar for the bees, such as nectar, aphid pee, or pine resin (yes, all of those go in).

The whole point here is that you need to build surplus capacity into your system. People, unless properly trained, have this horrible habit of using up their reserves. For example: "Oh, we have a 10% biomass surplus in our ship's ecosystem. How about we increase our population by 10%" Or, "Goats lose 90% of the calories they eat. We don't need milk, we can eat more plants."

This works in the short run. Then you have to kill crew members during emergencies, because you can't feed everyone. And then you have to recycle their bodies quickly. Cannibalism perhaps? If you don't have a mechanical recycler, that's the simplest way to get them back in the system. And these will be people you know.

That's why I'm talking about beer. And parties. In a pinch, people can do without beer. However, alcohol is so embedded in our society that it's hard to get rid of it, except in emergencies. It therefore makes a good surplus to have, because it's useful in the good times, and vital in the bad times. In an emergency, it's always better to forgo parties than to kill your suddenly excess friends.

Yes, other societies have done this. Go back and read Argonauts of the Western Pacific, for one example.

84:

heteromeles makes a good point - that your population is not decided by your average carrying capacity. Instead, it is set by the carrying capacity of your ship's ecosystem when that ecosystem is in its worst-possible failure mode.

European settlers to Australia saw the place as empty and the indigenous inhabitants as slothful and unproductive, ignoring the bounty of land available to them. What they failed to work out was that yes, in an average year, the land could support ten times the population density, but in a bad year the land could support just the tiny number of people who happened to live there. Given Australia's climate, a bad drought year can be followed by six more bad drought years with no respite.

So, relevance to long-duration starships: you need a population that can be supported by the biosphere, when everything that could possibly go wrong with the biosphere has just gone wrong. Pest infestation, and genetic bottleneck, and the poo pumps just broke down and the engineer who knows how to make the spare part for the poo pumps just got into a fight with the designated backup engineer for that spare part and they've both popped their clogs.

All of which suggests that a noticeable part of the mass balance of a starship will be safe stores of food & water to get through the inevitable times when the food & water system is in the process of being fixed. Worst case scenario - you have to reboot your entire biosphere, so you'd want to have a couple of years food and water stashed away.

85:

I'm sure you may have seen this - a call to TV adapt the Laundry series

http://www.techrepublic.com/blog/geekend/four-geeky-book-series-that-need-to-be-on-tv-now/7853?tag=nl.e010

'bout time.

Guy F

86:

Absolutely Jez. This is probably more realistic than the beer rule, especially for early efforts.

The Mormon rule of keeping a year's worth of food works here. So does the Mormon Basic Four (200-365 lbs wheat berries, 60-100 lbs powdered milk, 35-100 lbs sugar or honey, and 1-12 lbs salt per person, per year). Or you can follow the classic Andean rule of running civilization on one good harvest every five or six years.

With the Mormon rule, this is what you want your biosystem to generate as a surplus per person on a regular basis. With the Andean Rule, multiply it by six.

As a comparison, 8-15 pounds malt generates 5 gallons (40 pints) of beer, or 2-5 pints per pound of malted grain. In other words, if you're a heavy drinker by US standards and you like wheat beer, the beer you drink in a year is your emergency supply.

For planting you can use 100-150 pounds of wheat seed per acre to get up to 6000 pounds of wheat per acre--if you're in the Palouse, and you know what you're doing, and you're a bit lucky. These are very crude figures. Basically, a year's wheat supply for one person (200-300 lbs) produces enough for 40-60 people (4000-6000 lbs), under very good conditions.

The bottom line is that, if conditions are good, you can generate a lot of wheat in a season, and it stores well. Presumably, as Jez noted, emergencies are not optimal conditions. The nice part is that foregoing beer periodically can add up to a lot of grain saved.

87:

The thing about tens of 1000s of species in soil is that one can get them easily by bringing on board some soil. Not like one has to add them all individually.

Though that leads to a point about resiliency; natural stability doesn't seem designed at all, bad Gaia theories not withstanding, but a temporary equilibrium of selfish replicators, any of which might mutate so as to make a short-sighted grab for more resources. Whether imitating Earth ecology on the scale of a space ship is more resilient than having a bunch of redundant industrial processes designed for what you want seems an open question to me. Note 'industrial' could well include various bioreactors, no need for ideological purity.

As for societal redundancy, contemplate that the US has no public granaries, or "strategic food reserve" as we might call it these days; policy is to trust to the market. I don't know if any other countries do. Given the ease with which a large volcano can bugger up sunlight, I'd feel a lot safer with e.g. a three year food supply. Granted, the American grain-fed meat diet means there's a fair bit of slack, at the expense of eating livestock-grade corn and soybeans.

88:

There seems to be an implicit assumption running through this discussion that a mobile colony will be a closed system. I see no reason for that. It would need to be efficient and highly redundant, but fully closed? Nah. There is stuff out there folks. Also, any drive system will need to have its mass replenished occasionally. I imagine that it will be a big day for a generation ark out in the Ort cloud when it pulls up next to a nice big and dirty snowball and starts mining it.
I am reminded of Norman Spinrad's wonderful story "Riding the Torch" in which (IIRC, it has been a while) the survival of a fleet of colony ships depends on them learning how to harvest necessary components (on an atomic and molecular level) as they travel between the stars.

89:

It's nice that you mention Belgian lambic beers because the fruit variants (Mort Subite cherry and Mort Subite strawberry) are the only kinds of beers that I can actually drink. Any other beer makes me nauseous (and I've come close to vomiting several times when I tried to take more than a tiny sip) even though I love the general "street" smell of typical non-lambic beer.

So, I've looked into the delicious fruit lambics several times. Each time I've come back mystified. Basically they let nature take its course. They go by rhyming proverbs and that's about it "En hiver, brasse qui veut, en été, brasse qui peut." Meaning that they keep the brew exposed in winter to let the (relatively known) microbes in, and then stop brewing in summer to keep the (totally unknown) bad microbes out.

In other words, a Belgian Lambic beer seems to be the least likely to end up in a small-size closed ecology given the mysterious nature of the micro organisms involved.

Looks like I won't be setting foot on your interstellar ark! Of course, there is the small possibility that you might find a way to produce Drambuie, and then you can count me in.

By the way, glass and pewter aren't the only traditional containers for beer. I've taken a few vacations in Bavarian back in the 90s and I've seen a lot of pottery tankards in museums and for sale in gift shops. All you need is some clay and a few pottery furnaces.

90:

I'm not interested in going to the stars if I can't take chocolate with me. As Charlie has pointed out a number of times, the flight of a large colony can't be a stern and dour undertaking, there has to be some cheer and celebration along the way. And, to paraphrase Gilbert Shelton, chocolate can get you through times of no work better than work can get you through times of no chocolate.

91:

One could hope that genetic engineering could produce a smaller cacao-bean producing plant. No obvious reason you couldn't have a peanut-like plant producing cacao.

92:

In Europe, wheat yields of around 10 tonnes per hectare are possible, about 9600 pounds per acre. It needs attention to detail and pest control, and good quality land. Since the sort of environment we're talking about can be very controlled, temperature and light cycles and water supply, this sort of yield seems possible.

(This sort of difference is why getting the soil right is going to be important.)

Now, that sort of yield, in a long-term artificial environment, is going to depend on recycling of nutrients. Even a small percentage loss, over a year, is going to matter over a century. Nitrogen, phosphorous, and potassium are vital, and where in the Oort cloud could they be obtained from?

Nitrogen fixing from the atmosphere needs energy. Current processes need natural gas as both an energy source and a chemical feedstock.

Phosphorous and potassium aren't so easily obtained.

I suspect that even the Rothamsted experiments, started in the 1840s, haven't been running long enough to be useful.

93:

Honey is quite low on various nutrients required by the yeast. If you restrict yourself to honey, yeast and water then pure mead fermentation is often extremely slow.

Adding extra nutrients and modifying the acidity with a bit of fruit makes things go a lot more smoothly, but even then extra yeast nutrients are handy.

I just bottled some of the stuff last night, but I just realised I have no idea exactly what went into it :)

94:

Ok, still not a biologist, but I am a con-going SF fan, so I do have something to contribute.

We need sufficient brewing capacity to produce 4 pints per day for every person (including those too young for beer and those who don't like beer) on the starship. No cite available beyond my near certainty that someone else here can and will provide a verification if required.

95:

I've heard of Rothamsted in another context (WW2 agriculture) but googling on 'Rothamsted experiments has just opened my ideas to a marvellous vista. ABout once every five years I let myself be proud to be British, and this is one of those days. Get in!

http://www.rothamsted.bbsrc.ac.uk/Research/Centres/Content.php?Section=Resources&Page=ClassicalExperiments

Relevance for this thread: this research programme demonstrates an observed willingness to stick to a 150+ year timetable in scientific experiment. It's a little like weather observations, but different in that it relies upon continuous regular consistent and documented interventions.

96:

Mead is a nightmare compared to beer.

Consider: you need honey (lots of honey -- around 0.5 Kg per litre, if memory serves). This implies bees to produce the honey. Bees imply lots of flowering plants. They also imply a lighting system that can provide polarised UV light so that the scout bees can communicate the location of said flowering plants to their hive.

Worse: bees are small, stinging insects that explore. What happens when they (as will inevitably happen) start exploring somewhere they're not supposed to go -- like your recycling plant, or cable ducts, or residential areas -- in search of somewhere to use for a hive? What happens when they swarm? (How do bee swarms behave in microgravity environments, anyway? Especially if they get disoriented because they've gone somewhere where there's no background polarised UV field?)

97:

Charlie @ 96
Which means you are buggered for a closed environment anyway.
No flying plant-fertilising insects means ... no fruits or crops (Think: Beans, Apples, herbs, courgettes, many berries, etc....)

98:

I was about to add ...

Despite these obstacles it may be possible to accommodate bees on a starship.

You'd need to select a strain with a mild or non-existent sting, and select for lack of aggression. But at the same time, you can exclude macropredators like hornets that prey on bees (can anyone think of a reason we might need hornets on a generation ship? Other than one run by masochists who believe in self-mortification?).

You'd need to provide a background polarized UV light field above your crop areas. If you're really sneaky you could maybe provide a light field in the adjacent corridors that can be modulated so that if bees wander into them, they can be steered back towards where they belong.

And you'd need mesh or fabric barriers on the approaches to areas with bees and flowering plants in order to keep the insects in.

But honey, as such, is likely to be a luxury item; going by these figures it looks like you might get up to 200Kg of honey per hectare under cultivation per year from clover (and up to 1000Kg/hectare/year if you go specifically to cultivate plants that provide bees with maximum nectar -- but of no other use to us). Compare with the 10 tonnes of wheat/hectare cited elsewhere, and using growing space primarily for honey production looks like a bad idea.

99:
Compare with the 10 tonnes of wheat/hectare cited elsewhere, and using growing space primarily for honey production looks like a bad idea.

That depends on how you look at it. After all, you're making the alcohol as a way of ensuring that the population maintains surplus capacity that can be converted to primary food production in times of crisis. If your alcohol plants are an inefficient use of space, that means that you can persuade the population to retain a larger buffer in terms of field area. Which could be advantageous if the crisis renders some or all of your primary crop fields temporarily unusable.

If your wheat areas suffer a problem from which the soil will take five years to recover, say, then having a substantial flowering-plants area allows you to replant enough wheat to feed everyone in the mead region while still maintaining a buffer against further disaster. (And you only have to reduce the alcohol ration, rather than telling everyone to go without for a year.)

100:

The amount of honey required per litre of finished mead depends mostly on how sweet a result you want. Half a kilo per litre of mead gives you something that is quite sweet.

Drop that down to 0.2 kg/l and you get something that has a hint of sweet, but is about on-par with a not-quite-dry white wine for sweetness.

I don't have any degrees or nothing, but have brewed mead for close to 20 years.

101:

A hectare of wheat, producing 10 tons per year under intensive cultivation, will feed 50-100 people.

A hectare producing 1000Kg of honey per year will produce 2000-5000 litres of mead (although I suspect at the 5000 litre end of the scale you're going to be mixing in other sources of sugar to support fermentation). That's at best two bottles of dry mead per person per week (50 people, 5000 litres) -- possibly as little as one of sweet mead a month (1000 litres, 100 people).

(Ignoring the maturation time -- we have some demijohns that are about ready for bottling that have been sitting for 15 years in the kitchen closet :)

Brewing beer, you can get roughly 1 litre per 0.15Kg of grain, so you could in principle produce (conservatively) around 50,000 litres of beer, or 500 litres/year/person for 100 people (or around 3 US pints per person per day).

Do you want three pints of beer per day, or a bottle of mead once a month?

(Note that these are not exclusive offers; a large space colony can probably do both. It's just illustrative of what you can get out of the same amount of land, depending what you do with it.)

102:

"Harness the power of dust mites?"

Sorry, but that just conjured an image of millions of nanotec treadmills all whirring away

103:

If we're talking an orbital colony, sunlight need not be a problem, and crops such as clover can be grown, as part of a rotation, to fix atmospheric nitrogen in the soil. The bees also provide honey from the clover. Other crops are also dependent on bees for pollination, beans for instance.

And we shouldn't assume monoculture. There's nothing to stop wheat or barley being undersown with clover.

Take away the sunlight, as you would on a trip to the Oort Cloud, and and the energy the plants need has to come from somewhere else. We already know, from such things as the experience of Apollo XIII, that objects in space have a relatively low equilibrium temperature, compared to the planet we know about. But that doesn't mean that a deep-space colony can maintain a stable, comfortable, temperature and also generate sufficient false sunlight for the biological systems

Was David Brin doing some frantic hand-waving when he used a laser to refrigerate his Sundiver? Maybe our artifical sunlight needn't depend on black-body radiation, which would alter the thermal balance of the habitat. Yes, I know the light has to be the right colour.

104:

We're not talking orbital colonies -- we're talking long-duration habitats en route through the Oort cloud to another star system.

Moreover, AIUI O'Neill's big-glass-windows-in-a-spinning-cylinder design was thoroughly discredited; differential thermal expansion between the windows and the presumably-metallic hull would really fuck them up, and when you add the need for ten metres of cosmic ray shielding you end up with an unsupportable mass, unless you adopt an indirect illumination design (i.e. mirrors outside, reflecting sunlight down the long axis of the cylinder through an end-cap window, then bouncing it off a diffuser).

Was David Brin doing some frantic hand-waving when he used a laser to refrigerate his Sundiver?

Yup. It doesn't work. Second law of thermodynamics. (Mind you, as he had aliens and FTL starships in that novel I think that's the least of his sins.)

105:

I don't think it's necessarily an either/or question, given that you can keep bees and cultivate honey alongside other crops like fruit, vegetables, buckwheat etc. The amount of land you'd need to set aside for honey production in order to get a decent crop is negligible.

106:

"Harness the power of dust mites?"
Sorry, but that just conjured an image of millions of nanotec treadmills all whirring away.

Actually that's what our own bodies run off--about 10^16 mitochondrial ATPase treadmills, rotating at about 600 Hz.

107:

One company in the USA gets 250 tonnes of tomatoes per hectare using hydroponics

108:

Laser cooling works fine in small lab experiments, but might not be much use on a City In Flight, barring an improvement in the state of the art.

In 1999, the coldest place in the Solar System(*) was at Sussex University, where they used laser cooling to produce a Bose-Einstein condensate. In 2003 groups at Innsbruck, Boulder, and MIT produced molecular BECs.

There are several methods of using lasers to cool something. I expect the laser gets hot, so there's no need to call the Thermodynamic Police quite yet.

(*)and possibly the entire Universe? The hottest place btw was at Sandia Labs in 2006.

109:

differential thermal expansion between the windows and the presumably-metallic hull would really fuck them up

So why don't continental climate extremes ruin steel and glass office buildings for the same expansion differential?

The smaller O'Neill design was replaced by the "Stanford Torus" which used reflected sunlight.

The radiation shield was still a large rocky mass, but I think it was not rotating with the ring, so it didn't contribute to the structural load.

Granted that this is still a difficult design if the vehicle is accelerating.

So I am waiting to hear what the posited drive is going to be to move this mega tonnage of mass between the stars. At this point it is analogous to crossing the Atlantic by moving Jersey to New York.

110:

One company in the USA gets 250 tonnes of tomatoes per hectare per what time period?

111:

IIRC what Brin described was pumping heat into the laser and firing it out of the ship, which allowed them to stay nice and comfortable even when they were flying through the photosphere of the sun.

The sort of laser cooling they do in physics labs involves bouncing photons off atoms to slow them down, which is quite different.

112:

So why don't continental climate extremes ruin steel and glass office buildings for the same expansion differential?

Because they're not undergoing c. 500 degree celsius thermal swings within a period of minutes, from -200 in the shade to +300 in direct sunlight. (If you're periodically occulted by Earth while in orbit, the thermal gradients are savage, to say the least -- orders of magnitude greater than anything you get on the surface, thanks to the fact that we have an atmosphere as a buffer.)

It might be possible to make an O'Neill cylinder work properly (with direct sunlight) if we ditch glass and go for something more exotic -- diamond, maybe -- and use an opaque version of the same material for the load-bearing sections, reducing the potential for differential expansion. But it's probably easier and safer to use an indirect design instead.

Acceleration may be less of a problem, if we posit continuous levels of very low acceleration -- on the order of 1mm/sec^2 to 1cm/sec^2 (i.e. 0.0001 to 0.001 gees). Objects "falling" within the cylinder will drift towards the rear, but if you're falling from a height of 10 metres you'd land only a few millimetres out from straight down -- the Coriolis effect would be greater.

Propulsion is a problem. But I think we can agree that the time scale it'd take to build such a space colony would be at least as long as the time scale we will need to explore aneutronic Boron-8 fusion; or, failing that, to get our hands on a couple of gigatons of U238. Think in terms of fast breeders powering scaled-up FEEP thrusters using Caesium fission fragments produced by the reactors as reaction mass. Or something. FEEP is good for an Isp of 12,000 within the next decade (according to a presentation I caught at 100yss); I think we can probably push ion thrusters a lot further than that.

If anything, the real problem will be getting rid of waste heat from the reactors that power them. What we really need is some way of getting around the Carnot cycle -- direct conversion of captured neutrons into electricity (without having to dick around with high temperature steam cycles and turbines) would be brilliant, for example.

113:

ah, I see - I haven't read the Brin. That sounds barking. Now I'm going to waste half an hour wondering what he meant by that, or if it's just wrong. Brin's a physicist, so he should know better?

114:

Once you let six different flavours of FTL drive into your universe, what price the second law of thermodynamics?

(This is one of the reasons I get annoyed with much so called "hard" SF; allowing one impossible thing before breakfast and exploring its consequences is all very well, but once you start counting the stacked impossibilities in a late-period Niven "Known Space" story ...)

116:

Speaking of stacking, the permaculturists have a great concept that can help here:

stacking functions.

In permaculture, every organism a bit of land supports is a function. So is nutrient cycling, so is every weed not supported, so is water purification, etc.

Their ideal is to stack as many functions onto their land as possible: support a lot of organisms, a lot of diversity, and so forth.

That's a good way to think about starships. It's not about bees or wheat necessarily, but it is about having a function stack of plants that require pollination, so that your bees can forage through the year, and provide you both with pollination services, honey, and wax.

As for bacteria, functional diversity is more important than species diversity, especially since they'll evolve and diversify en route. You need to make sure there's at least one (if not a dozen) bacterial strains for every microbial-led transformation of an element in every elemental cycle in the system. The most important example is in the nitrogen cycle, where you have to have enough nitrogen fixation (probably through rhizobial bacteria) to make sure that all your nitrogen doesn't end up in the air.

You do that for every elemental cycle, and you've got a chance at having a functional system.

The counterexample is to blindly follow organic farming principles, as they did in the first Biosphere 2 mission. They had a lot of problems with their carbon and oxygen cycles. Much of their oxygen got sucked out of the air, apparently by the microbial biomass in the highly organic soils they insisted on using, against the advice of soil scientists who told them to use argely mineral soil. CO2 levels didn't immediately jump as the oxygen dropped, because the new CO2 got sequestered into the still-curing concrete (carbon lost to their biosphere). Nonetheless, CO2 levels fluctuated wildly (600 ppm/day, 3500 ppm/year) because the plants drew down CO2 in sunlight, respired much of it back at night, and growth varied throughout the year following seasonal patterns. They suffered on that one.

117:

I don't see why you can't use lasers to cool a starship. Laser is an effect, and can be thermally pumped, it doesn't have to be something that draws power. Just pump all of the excess heat into a single area.

118:

This isn't a trick question at all. At least, it shouldn't be regarded as such. It's the generation ship equivalent of the Popsicle Test in urban planning and development. The Popsicle Test reflects other concerns I have about generation ships and other long-term habitations. Designed wrong, they could become another Pruitt-Igoe or Kowloon Walled City. The challenge here is to design not just for efficiency, but for humanity. The Beer Question addresses that.

This is a roundabout way of saying that maybe the question isn't necessarily "how do we brew beer in space?" but "how do we brew beer in urban space?" If generation ships really are cities with engines, as Charlie has said, then maybe we should propose cities as closed systems and think about how they would solve the problem.

120:

Depends how long you ferment it. That's the amount of honey I used, and I'd ferment to dryness. Yes, it was quite strong.

121:

An exciting side effect of having all those microbes in the soil is the potential for mutations into Space Plague.

122:

Things I am learning from this thread: Everyone who makes mead does it completely differently.

123:

F's definition of "quite strong" is somewhere in the range 15-20% ABV, near as we can guess. (Some of her efforts bear a distinct odour of alcohol when you pull the cork.)

124:

So what is the max % of ethanol one can get from a fermentation process before the yeasts die?

125:

I made a couple of batches near the 20% mark when I started out, but found that I preferred it a bit weaker.

It tasted OK, but something undefinable made it feel "wrong". Non fermentable sugars and other gunk pushing up the viscosity was my guess.

Cutting back on the honey to aim around the 15% mark seems to be about right for my taste.

126:

20% is generally about as high as normal yeast will tolerate. You can probably nudge that by a couple of percentage points if you breed your yeast for alcohol tolerance.

Freezing the product and discarding the ice from on top will get you up over 40% ABV without you needing to go so far as to set up a still.

127:

Heat is high-entropy energy, and you're trying to get rid of the entropy. Lasers are zero-entropy. If you needed to cool yourself while in the sun, you'd do it with conventional air conditioning cycles, except you'd be venting plasma hotter than the surrounding plasma. Not a laser. That'd be like cooling your apartment by making ice cubes then throwing the ice cubes out the window.

128:
It may be cheaper to do it the traditional way, on earth, but perhaps not in a mass/space limited environment. If you can accept that for beer, or wine, then you can consider that it is possible for other foods too. Algae based steaks - indistinguishable from steers.
It seems unlikely to me that we can engineer a biotech system of a few species of bacteria that can synthesize complex mixtures of diverse organic molecules as efficiently and as reliably as systems that have evolved over the last few billion years. And I'm not sure what the advantages would be. If we want meat, at a minimum we can culture muscle tissue on an industrial scale (this should be commercially practical in the next 20 years or less), and at worst we can raise meat animals in the old-fashioned way. But trying to keep a big vat of algae producing exactly the right mix of chemicals (and then processing it to produce the correct textures and consistencies) seems unnecessarily difficult.
129:

Charlie's about right. There's research in increasing max. ethanol not to mention increasing rate of ferment & heat tolerance in bioethanol processes. The problem is that ethanol is toxic, and eventually the yeasts stop fermenting & die.

It will come as no surprise that I am a fan of yeasts; they can be harnessed for a number of useful functions (brewing, winemaking, bioethanol production, breadmaking) not to mention providing raw material for Marmite/Vegemite.

130:

The big advantage of animals in general is that they eat material that's inedible for humans, and turn it into things we eat or use. This can be meat, milk, eggs, hides, horn, and/or manure.

With regard to the manure, feeding waste to an animal is one of the fastest ways to turn into fertilizer. Mammals and birds do it in a day or two, worms in a week or two. Composting without animals takes 16 days minimum.

As for efficiency, space designers have traditionally looked at goats, chickens, and rabbits, rather than cattle. Cattle are too inefficient at producing milk or meat to be serious contenders. Pigs are a borderline candidate. On one hand, they are more efficient than other animals at turning food into meat. On the other, that (and producing leather) are all they're good for, and because they're ruminants, they can't eat the most frequent agricultural waste, high cellulose plant stems.

As for diverting nutrients to grow some sort of cell culture that will taste like meat, they're already experimenting with that, both with fungi (quorn) and animal stem cells. There are problems. Quorn, while tasty, isn't much like meat, There are major issues in getting muscle cells to organize into something other than a homogenous culture. Texture is as or more important than flavor for these things.

To be blunt, I'm not sure it's worth doing. Artificial meat cultures certainly save space, but it's abstracting and/or faking a single animal function and putting it in a mechanical subsystem. As recyclers, animals are multi-taskers, and that makes better use of scarce space and mass.

131:

This morning, I was contemplating how to get to the stars from here. Perhaps it was reading David Brin's blog.

Anyway, we're talking about beer in space, but from the confusion, I think we need to test this a few more times on Earth first.

Arcologies are a great idea, and we need to put them in as many harsh places as possible, ideally as luxury arcologies for the off-shored rich.

Those floating sea-states the libertarians are toying with would be one place to hone our skills certainly, and I think that areas such as Australia's western desert, Greenland, and Antarctica would also work. Politically, I'm not sure how the Atacama Desert, the Sahara, or north Dakota, Siberia, or the Taklamakan desert, but those are possibilities as well.

That's my thought: we hone our trip to the stars by building arcological retreats in uninhabitable places around the globe. Once these are successful (and all brewing their own beer) and supporting thriving populations, we can put them in orbit, then strap the motor on and ship them out of here.

What could possibly go wrong?

132:

That seems odd to me. How about, as a comparison point, using mirrors to create a directional heat beam instead?

procedure: use a small, black emitting ball at high temperature, put a hemisperical mirror of 10* the emitter radius on one side, and a parabolic mirror on the other side. The emitter should be at the focus of both. The energy sent to the hemispherical side should be reflected back into the emitter, the energy sent to the parabolic side should be sent in one direction, as a beam with a low dispersion.

133:

>>>>How do bee swarms behave in microgravity environments, anyway?

You are not seriously proposing a space colony without rotational gravity? What, a tether and a counterweight is too much for space civilization?

134:

You are not seriously proposing a space colony without rotational gravity? What, a tether and a counterweight is too much for space civilization?

No, I'm not proposing that. But inside any rotational system there's a point where the rotational gravity is close to zero, and if the biosphere encompasses it, and we have beehives, sooner or later we'll find bees there.

It would really suck to find that (a) bees like free-fall hives, and (b) we've built mission-critical hardware right where they want to build them. (The idea of trying to deal with a swarm in free fall does not fill me with joy.)

135:

>>>What we really need is some way of getting around the Carnot cycle -- direct conversion of captured neutrons into electricity (without having to dick around with high temperature steam cycles and turbines) would be brilliant, for example.

Neutronovoltaics!

136:

>>>No, I'm not proposing that. But inside any rotational system there's a point where the rotational gravity is close to zero, and if the biosphere encompasses it, and we have beehives, sooner or later we'll find bees there.

I'm proposing a LONG tether. The point of zero gravity will be far outside the space station. Unless we are talking about futurama-style space bees (larger than most Buicks and twice as ugly), they shouldn't be able to live there...

137:

>>>it seems unlikely to me that we can engineer a biotech system of a few species of bacteria that can synthesize complex mixtures of diverse organic molecules as efficiently and as reliably as systems that have evolved over the last few billion years

Why? We already do stuff that no amount of evolution can get to.

138:

Sorry; I wasn't clear enough. My point is that you can view the need for a much larger region under cultivation to produce the same amount of alcohol per person as a benefit. If you do produce the same amount of alcohol, that means that your reserve area (not in use for vital food production under normal circumstances) is much larger than it would be with a more efficient setup.

That extra backup comes at a cost, of course; a ship of the same size but with more space devoted to alcohol production necessarily supports a smaller population. So the question is one of where you draw the line between efficiency (carrying more people) and redundancy (keeping those people alive in an emergency).

So the relative inefficiency of mead-production as a use of the field space could be an advantage, depending on your priorities.

Do you want three pints of beer per day, or a bottle of mead once a month?

Personally, I'll take the mead every time. But I'm aware I'm a bit unusual in that. :)

More seriously, for the usage cases I'm thinking of, the question should be "Do you want your ship to support a population of n people drinking mead, or a much larger population (say, 5n) drinking beer?"

139:

Pigs...pigs are *great*. Fast-growing creatures that eat anything and taste good. And they're really fun to be with, too. Not quite as bright as octopi, which is handy as they'd be way more trouble if they were and it would be troublesome to eat them.

I think, however, it might be good if the starship was microbiologically less like a damp back alley in the outskirts of Guangzhou than it's sounding. Pigbugs*chookbugs*people = not good.

But on the other hand, pigs are almost as great as beer!

140:

"And you'd need mesh or fabric barriers on the approaches to areas with bees and flowering plants in order to keep the insects in."

I think you'd need more than a mesh or fabric barrier. I think you'd need something nearly foolproof. I think you'd need regions of "hard" vacuum to isolate the bees and other flying and crawling thingies. Even then a few will always sneak into pockets, purses, and PDAs of people going through airlocks and you'll have to invent something to round up those strays in a regular fashion.

A lot of flying and crawling thingies are necessary at least in one isolated sector to maintain a balanced ecology, if only to calibrate in a regular fashion the more "controllable" bio constructs that will replace them in most of the agricultural sectors of the ark.

I also think that you'll need three arks, flying in formation, just in case. You don't need as many as in Spinrad's "Riding the Torch".

141:

Absolutely agree with you. Tissue culture is going to be preferable to algae. Both are preferable to supporting cows in the habitat, unless you desperately need cows at the target destination and there is no means to recreate cows from DNA/frozen ova.

142:

The O'Neill colonies had separate ag areas from the main habitat. This allowed the farms to maintained differently and to expose them to vacuum, high energy, etc to sterilize them if necessary.

I'd keep my bees there too - although that does mean flowers in the hab areas will need to be pollinated some other way.

143:

We haven't mentioned the unknown problems with free fall on all the other organisms in our study. Why worry about the bees?

Another alternative is to see if stingless bees work better inside a spaceship. They do produce honey, and they really don't sting. They bite instead.

144:

It would really suck to find that (a) bees like free-fall hives, and (b) we've built mission-critical hardware right where they want to build them. (The idea of trying to deal with a swarm in free fall does not fill me with joy.)

I'm confident that as soon as we have bees in space we'll soon thereafter have bees in places we did not put them. (I won't even dismiss the idea of bees going EVA and coming in through the airlock by clinging to somebody's suit.) And while a few studies have been done on spiderwebs in free fall, I'm unaware of any beehive building experiments. Quite a lot of electronic rack-mount equipment, and particularly things with card slots, look remarkably like the popular Langstroth hive...

145:

The Parker test for wine would be good - if he likes it, you can throw it out the airlock and not risk anyone else having to taste it ;)

Thank God he's retired, now we will get back to decent Californian wines again, not over extracted over alcoholic fruit bombs. The guys' tongue is clearly leather.

146:

It appears that some researchers were lobbying to put bees on the space shuttle about 5-10 years ago. Obviously that didn't fly.

147:

I think in this scenario, it's more about the support infrastructure required & the failure modes thereof: which is easier to diagnose & fix if it goes wrong? The meat animals or the culture of muscle tissue?

148:

Wearing my best pedant hat, a ring can be made to rotate for the gravity effect, and also have thrusters around the perimeter to avoid the need for a zero-G section altogether. It could make for a ludicrous last-ditch "dodge" of large objects, but I was more thinking that technically a ramdrive doesn't have anything in the middle of it either. Wrapping a ring around some sort of ram drive would give you overhead lighting as well as gravity. At the extreme it'd be a ringworld...

I suspect anything primitive enough to require forced cooling would be unattractive to bees, ours seem to be much more interested in building new hives in inaccessible places that are expensive to get them out of (I regard them as microcats who make honey).

149:
It would really suck to find that (a) bees like free-fall hives, and (b) we've built mission-critical hardware right where they want to build them. (The idea of trying to deal with a swarm in free fall does not fill me with joy.)

A swarm is relatively easy to handle in an enclosed space, by introducing gas or removing air. That's not going to be your big problem.

This is: bees are small creatures that like to crawl into spaces the same size as themselves and build large, sticky, strong structures out of wax. Without a 100% reliable way to control them, they will eventually get into everything and gum it up so that it can't move. A substantial amount of labour would be required to check everything important frequently and clear out any infestations, and everything would have to be designed with the added requirement "ability to take it apart every week to search for bees". I don't really see it being affordable.

150:

Chemical and legal point.

Charlie is quite correct about it being possible to evolve non-distilled spirits in the 40%s ABV by freezing and discarding the evolved ice.

Unfortunately (for us) unlicensed freeze separation is every bit as illegal as unlicensed hot-distilling, despite it not carrying the same health risks.

151:

Charlie Said "I'm going to nail my euro-socialist colours to the mast right now and say at this point that throwing them out of the airlock is not an appropriate way to deal with this problem"

Indeed not, Mr Stross, because obviously we'd want to compost them back into whatever passes for soil. I don't think throwing anything out the airlock would be appropriate.
The only thing that leaves the, er, arcology (?) would presumably be reaction mass, and I'd expect that to be rather less important than compost-able stuff like surplus people.

152:

So it's hornets then. You know, I'm mighty fond of this solar system. If the Good Lord had meant us to go beyond the Kuiper Belt, he'd have made pollenators more tractable.

153:

If you liked Snakes on a Plane, you'll love Bees in a Shuttle...and yes, taking things apart regularly to check for bees would be teh suck.

154:

I see most people just are trying to get some variety of the 1980s or 1990s in space. I believe humans for the space colonies will need to be "modified", and so will be their ecology and food sources. I suspect they will be simplified, and more so as time passes.

I also agree there will be something called beer, a low alcoholic drink that doubles as foodstuff, vitamin supplement and social gathering lubricant. I doubt it will be made from barley, or wheat, but who cares. After the first generation dies off, complaints about the taste will stop and a new connoisseur culture, based on different strains, brewing, additives(I am sure I was not the only one to experience with fruit syrups in my youth) and geographical location within the ship.

This is a new step in evolution. What worked in Earth is not what will work in space, but as we are not sure what works, we will need to take several alternative systems in case the first bets fails. In that case there may well be a difference if the ship just will drift through the void forever, or if it is expected to make landfall at some point in time, as the second case will make it necessary to keep a backup ecosystem or two, and as much variety as possible, while the first one could be tackled by building tailored organisms as needed.

155:

I don't think that anyone has quite made this explicit.

Beer and bread both depend on a grain crop and yeast. Hops in beer are, strictly, an option, and the yeast varieties are also different, but if your system cannot produce one, it is going to struggle with the other.

That's one of the reasons why beer is a good way of managing surplus capacity.

Now, it might seem a little odd to us to be talking of a wheat beer, or of barley bread, but beer and bread are far more interchangeable than some of the alternatives. And, while the grain varieties can differ--protein levels come to mind as a factor--biscuits don't need the grain protein that bread does.

I'm not your expert on brewing, but I've grown a few thousand tonnes of grain in my time, and matching the qualities of the grain to a particular market does matter. The guys on one of these habitats, moving or not, have some huge advantages. They control the weather and have uniform soil. They're not running everything in a single seasonal growth cycle. And it won't be a market-economy. They will be able to adjust the "weather" to shift the protein level of the crop, and harvest the grain with a low enough moisture level for storage, rather than getting the ripe crop rained on.

We may be able to breed crop varieties which take advantage of these things. Part of the "green revolution" in wheat crops is the use of a "dwarfing gene", giving a much shorter crop which can put more energy into grain, and less into the structure of the plant. In a hyper-controlled environment, we maybe don't need quite so strong a stalk, to resist the damaging effects of heavy rains. Similarly, we might have a longer frost-free growing season. A "winter" wheat needs some frost, but not as much as you would get in Minnesota. It starts growing within a few weeks of the last harvest, maybe gaining a couple of months of growth, compared to spring-sown wheats.

Oh, and the same for barley.

And I suppose I had better mention triticale.

156:

I'm a bit puzzled as to why there's a thermodynamics (as opposed to a practical/engineering) problem with Brin's sundivers. From a thermodynamic point of view, it's just refrigeration: I'm moving heat from a cool inside to a hot outside. (I'm running down my unobtanium power cells painfully fast, to be sure: the outside is ~100x the temperature of the inside, so pumping one joule of heat costs me ~100 joules from my power reserve even at the thermodynamic maximum.)

I can quite believe that there's no (or no remotely sensible) engineering way to do this that involves firing a laser beam into the chromosphere, but I'm not clear what thermodynamics has to do with it. (Am I missing something?)

157:

Would this lead to the evolution of SBB (Starship Brewed Beer) to match the IPA India Pale Ale which was developed so that it could survive the sea trip to India? The charactersitics of this beer such as high levels of hops became popular at home in Britain The passengers/crew might learn to love whatever can produced.

Of course if you have the ingredients for beer you can leave out the the hops and distil to get whisky. It might take a while for the peat beds to mature sufficiently and the ship would have to be big enough to have an ocean analog to leave the barrels beside for a few years.

158:

I see most people just are trying to get some variety of the 1980s or 1990s in space. I believe humans for the space colonies will need to be "modified", and so will be their ecology and food sources. I suspect they will be simplified, and more so as time passes.

Er, no.

Firstly, the reason behind this discussion (and other earlier ones) is that I'm fascinated by the prospects for human space colonization in the absence of certain technology breakthroughs; in other words, what if we don't get [any one of] strong AI, lightweight fusion reactors, a general cure for cancers, or better materials. Obviously any one of those items would make the job a whole lot easier. How to do it in their absence is therefore a much more interesting (and less tractable) problem.

Secondly, agreed 100% on the need to modify humans -- but it opens up a gigantic ethical can of worms. (Are you volunteering to modify your children so that they'll be better adapted to a particular job?)

As for the simplification -- no, I think it's going to go in the opposite direction, because increasing complexity has been the underlying subtext of evolution in general and human cultural development in particular all along. A human culture that can adapt to space is going to be a superset of the baseline human culture that can only exist in one small corner of the environmental envelope its planet of origin has passed through during its history. (I'm going to leave this as an unsupported assertion for now, but it may turn up as a blog entry later, when I have time to build a proper argument for it.)

159:

You don't need peat beds for whiskey, only for the peated varieties. Most of the Irish ones for example don't rely on peating for flavour.

160:

#153 - I loved Snakes on a Plane; it's a shame that none of the rip-offs managed to figure out that the killer SPS were concept and writing (the cheap bits) rather than FX and Samuel.

#155 - Wheat beer (cloudy I hope) is specifically included in OGH's definition of "decent beer".

#159 - "Irish ones for example don't rely on peating or have much flavour" surely? Yes, I have drunk Irish whiskey, and will conceed its smoothness, but was sorely disappointed by the lack of complexity and flavour. Given the cases of Sourthern Islay and of Dufftown, where you get several distilleries producing distinctive Scotches within a few miles of each other, I'm sure you'll agree that Jameson's boast of having moved the distillary 100 miles from the original site in Dublin and still making whiskey that tastes the same proves that Scotch is the more complex product.

161:
I suspect they will be simplified, and more so as time passes.

Nuh huh, I'm not getting modified unless I get a Swiss army digestive system and/or the ability to survive in vacuum.

Make me photosynthetic while we're at it, and cut the middleman.

162:

If you're going to take Jameson as representative of Irish whiskey, then we might as well not bother (Do you drink Jack Daniels and condemn the American distillation industry?). If you like peaty, I suggest hunting up Connemara whiskey.

163:

Whoops, sorry, didn't realize just how snarky that would read. Please mentally insert missing emoticons. ",)

164:

(Am I missing something?)

Well, what do you think happens to the laser device's outer surface when you run a laser continuously? It gets hot! Energy conversion is always lossy. So you're taking diffuse heat energy from the onboard environment, and using some energy in the form of electricity to pump it into a laser beam. Energy in: X+Y. Energy in the laser beam is (X+Y)*the laser's efficiency. Where does the difference go? - right back into the ship environment as waste heat! At the very best it would be hideously inefficient.

Airconditioners and refrigeration systems, of course, put the pump *outside* the volume to be cooled, and they can do this because the atmosphere carries away heat much better than a vacuum.

Brin's use-case was reducing the spacecraft's IR signature in order to stop enemies observing it. In that sense it would be worse than useless, as the waste heat from running the laser would certainly be enough to give a passive IR detection against the very, very cold backdrop of spaace.

165:

Brin's use-case is suggested by the name of the novel in which it appears, Sundiver; keeping the interior of a spaceship livably cool while footling around the chromosphere.

166:

Not an issue; I can be pretty snarky about the superiority of single malt Scotch (preferably an Islay, yes) over any other spirit I've tried.

I avoid most American industrial chemistry plants trying to produce recreational alcohol too!

If you can give me more of a steer than just "Connemara" it would be appreciated.

167:
If you can give me more of a steer than just "Connemara" it would be appreciated.

How about Laphroaig? Tastes a bit odd at first . . . but it grows on you. And in the U.S., rather expensive.

168:

Laphraoig is a classic Islay malt, and one of my favourites. Perhaps Anonemouse now realises what he's up against though?

169:

One way to think of this is David Sloan Wilson's concept of path dependence.

Background: Dr. Wilson is an evolutionary biologist who's taken to seeing how evolutionary theory can help run cities (see The Neighborhood Project).

His point is that, as with evolution, societal change is path dependent. Just as humans won't naturally evolve wings any time soon, our current society won't change to let any humans modify humans to have biological wings any time soon. This is a simple way of saying that culture and ethics matter. Sometimes you can't get there from here.

This is a huge problem for starship concepts, from governance to physical design. I joke about letting the crew get drunk occasionally, and some people focus on the alcohol and ignore the point about it being necessary to have surplus resources and ways to keep the ship working when people are incapacitated. That's our society, altering our perceptions. For us, alcohol is a focus magnet.

Here's a similarly problematic statement: can the mission survive if the captain gets pregnant? It's got a similar set of cultural trip-wires. First off, can a female run a starship, and secondly, does she take a lifelong vow of chastity. If she does not, how does the ship deal? How does she deal with caring for an infant and caring for everyone on board?

Societal path dependence matters. I happen to agree that we'll have trouble getting to the stars from where we are now, but that doesn't mean we shouldn't think about it.

170:

I'm more a Bowmore fan, but Laphraoig is good.
I didn't give you more steering because, well: http://www.connemarawhiskey.com

171:

Whisky/Whiskey
Well
I like all the Highland-&-Island singles... as for Irish, there's only one - the (Claimed) oldesty legal distillery in the world: Bushmills, preferably the 10 or 15-year olds.....

172:

...In the end, there can be only one?

That actually sounds sufficiently appealing that I'll be looking in gantry collections in future.

173:

Actually, you really ought to take the Yamazaki single malt for a test drive. Yes, it's Japanese, and yes, it's produced by Suntory, whose reputation is legendary (and not in a good way). But it's a remarkably good Islay clone!

Apparently a quarter of a century or so ago Suntory's CEO got sick and tired of being sniggered at behind his back and told his minions, "make us a good single malt, or apologize for it in the traditional manner ..." (or something equally motivational.) And eventually they got it right.

Only trouble is it's matured for the usual 12-20 years, and you can imagine what the rent on a Japanese bonded warehouse is like. Which is to say, it's not going to undercut equivalent Scottish malts on price any time soon.

174:

If this was anyone other than Feorag or you posting this, I'd be accusing you of trolling right about now. As it is, I'll be looking for a rich mug somewhere...

175:

Nope, it's genuine.

Remember back in the 1950s and early 1960s how Japanese cars were cheap crap, and they manufactured consumer goods that were too rubbish for even Hong Kong?

Not any more.

And it turns out they've done the same to single malt, just as their microbreweries have for decent beer (if you can stomach the £9-10/US pint price tag for cask-conditioned).

176:

Yamazaki I'm not incredibly impressed with - just my taste, nothing wrong with the whiskey - but Hashuku is worth trying.
@Greg: the 10-year is too smooth for me. I have been told to try the older ones, though.
@paws4thot: it's a product of Cooley Distillery, which is the entire other side of the country from Connemara, and the antithesis of Bushmills - only started making whiskey in the 80s. They bought up a lot of the old Irish whiskey marques and started producing under those names. (cf. Tyrconnell, whose original distillery quit in 1925)

177:

This generation ship's going to be pretty big and expensive anyway, so why not just stock up with a million bottles of Laphroiag, and a few hundred thousand bottles of rum, etc? I know it's about ecosystems really but how much can 10,000 people drink in a century?

Quick calc suggests ten million bottles of spirits would be enough. It's a sin to suggest it, but a lot of the water can be left out. So a bit less than a tonne of alcohol per person.

Going with cannabis, unless I've got my sums wrong you'd need 0.2 tonnes per person.

178:

Ten thousand? I expect the number would be a lot closer to ten million.

179:
Here's a similarly problematic statement: can the mission survive if the captain gets pregnant?

Brin had his early Earth starships crewed almost entirely by pregnant women, I think the reasoning was it made them risk averse and far less likely to get Earth into trouble in a densely populated universe full of obnoxiously hierarchical aliens.

180:

Okay, ten million it is then. Wow, that's a lot of booze and pot. You're right, better to grow it en route than carry 10Mt of drink and 2Mt of dope. It'd probably take a century just to stock up.

181:

I think the point of the question posed by our host is not to come up with ways of storing drink for everyone, but to discuss the issues of closed ecologies.

Two more points;
1) The mass the colony will have to carry if it just carries the ingredients will be more than if it just carried the finished product. However this is ok because the ingredients can be recycled and used for multiple things.

2) There is no "there". This isn't a ship travelling from A to B. This is a mobile self-sufficient colony.

182:

Any particular Japanese beers you could recommend seeking out? Thanks.

183:

Yes, I do realise that, mate: "I know it's about ecosystems really".

I expect that in a thread about a "100-year starship", it would be going somewhere (so there is a "there"), or at minimum turning round after 50 years, and that not everything it carries has to be made from scratch and en route.

If there's no "there" and the colony travels indefinitely, then of course the ingredients will weigh less than the finished product for long enough values of T. I wonder what the break-even point is.

In an earlier discussion I was on the side of the group that advocates not landing at the destination - and to make access to raw materials easier and to minimise exposure to any alien pathogens etc, I suggested that part of the ship not slow down at the midpoint. With a big enough ship/colony/city in flight the advance payload could do significant damage to an ecosystem, if aimed correctly. (It would probably take an impractically large lump of stuff to break open a planet).

In other words, anything you can't recycle or no longer need becomes warhead.

Excluding consumables, though I can't think of a specific example off the top of my head I'm sure there are many things that are easier to produce on Earth than onboard.

184:

That's in my category of "practical/engineering constraints". It doesn't have anything much to do with the 2nd law.

185:

No, the 100 year starship thing came out of DARPA, not my imagination. If it was me, I'd be pushing for a 1000 year starship program -- but I fear that would strain the credibility of US congressional budget processes.

186:

And to boost the "birth rate" of the colonies that were those ships' destinations.

187:

As an experiment, I'd suggest taking a surplus container ship (perhaps one of the ones from the Malaysian ghost fleet?), and fitting it out with a test ecosystem to feed the crew indefinitely. That would start to give us a handle on just how hard this all is.

As an extra, making the ship economically viable in some way would be really useful.

The nice thing about this experiment is that it's doable now, and at the very least, it could be a billionaire's secret lair/independent microstate.

188:

The 100 star ship thing I just ignored because of the whole idea of a ship going and coming back isn't just what's on discussion.

I agree with you, I don't see why the colony would bother to "land" (as in empty itself out onto a planet and live the classic space cadet dream). Instead they could just utilise the resources of a system to build more habitats of perhaps bigger/better types.

189:

I am right now sipping a Yamazaki 10 year old, and it's quite acceptable. It's part of my stash of unorthodox whiskies - which also contains a Welsh one, an English one and even a French one.

The French one is not really to my taste, but the English one (the Chapter Six) is really very nice indeed for a three year old. I'm seriously tempted to try to track down some of their Chapter 3, which is only 18 months old (and therefore not actually a whisky), or even the Chapter 1 (straight from the still!).

190:

"A human culture that can adapt to space is going to be a superset of the baseline human culture that can only exist in one small corner of the environmental envelope its planet of origin has passed through during its history."

Yes, quite true, and also true for a tweaked human species designed for that cultural adaptation.

191:

A report on the BBC, with accompanying radio programme. on how cultural expectations tell us what to do when drunk.

Anyone who has been to a British SF Convention will have a good idea of how different culture can give different results. We can drink the hotel dry before the weekend is half-over, but we don't act as we're expected to. The exceptions are notorious because they are exceptions.

192:

Ok, cleanup from ~17:00 yesterday on:-

Charlie, you took my last exactly backwards: I meant that I believed that Yamazaki existed, and was expensive but worth trying precisely because it was one of your posts.

The whole "generation ship making its own booze" thing is a sustainability test rather than an attempt to buy up several decades of $distillary's output.

Dave Bell - I'm sure you'd agree that many SF fans can spend more or less the entire weekend "with drink taken" but never "drunk to the point of obvious imparement"?

193:

As I was heading home from the pub last night, contemplating making myself a bit of toast when I got home, the answer to the question came to me:

"Ancient Egypt".

194:

Here's a similarly problematic statement: can the mission survive if the captain gets pregnant? It's got a similar set of cultural trip-wires. First off, can a female run a starship, and secondly, does she take a lifelong vow of chastity. If she does not, how does the ship deal? How does she deal with caring for an infant and caring for everyone on board?

In the future, we won't have... maternity leave? Seriously, if your mission can survive the captain dying, it should be able to survive her undergoing any less serious and less permanent medical incapacitation.

195:

DB @ 191
Like major Beer-Festivals.
Every time that GBBF has re-moved to London, including the first @ Covent Gdn, the Plod have screamed, sent thousands, "suggested" all sorts of ridiculous restrictions etc ...
Total number of areests, any year, is about 3.
They had to be told this @ Ally Pally & Olympia, the first years we were there.
Or - the difference between the policing and street disturbance during/after a Rugby as opposed to a football match.
Something the vile anti-drink Puritans conveniently ignore.

196:

I'd go further - if you take Charlie's view that in order to succeed the vessel-formerly-known-as-a-ship is actually going to have to be a Nation-State-Formerly-Known-As-A-Ship I think you're going to have to deal with the possibility of your "Captain" being unelected halfway through a programme of navigation / government.

Getting booted out of office is going to be at least as disruptive to the smooth running of NSFKAAS as maternity leave.

A wise crew would be advised to make their comfort and safety as undependent as possible on the abilities of one individual.

197:

I've heard it asserted that Glastonbury Festival is safer and has a lower crime rate than a typical town of the same population, so maybe there's a lot to be said for intoxication of all kinds.

Certainly the folk festival(*) I was a site manager for only had one accident, when I cut my hand on a fence - and one arrest. We called in the police to investigate the theft of equipment overnight, and they managed to arrest a 17 year old lad for smoking some homegrown in the carpark.

I was sick on a badger one year after too much Harveys, but I was very young at the time.

I wonder if part of the difference in behaviour is due to the insane sugar rush caused by drinking factory lager? I can easily and happily drink half a dozen or more pints of bitter over a day and still get work done, but more than a couple of pints of cheap lager and I have to lie down somewhere.

(*)Sidmouth. Greg, you're a Maresco dancer aren't you? I expect you've been there a few times and seen the non-occurrence of serious crime.

198:

I think the Japanese have a cultural appreciation for works of artistic craftmanship which, coupled with their industrial strategy of having a really, really good think about how things work makes Japan the kind of place that would host really, really good producers of Scotch.

199:

I agree. The issue is that our (US) society at present, allows males of reproductive age into the halls of power, but still seems to get squicky about allowing females that same privilege. Fortunately, this is changing--I recall a US governor (not counting Palin) who had a child in office.

This gets at one of the fundamental problems of starships--they're technologically difficult, and potential solutions include things like tiny crews, extreme lifestyles, and such. Conversely, people on a generation ship have to breed. But not too much. How do you balance that all out?

Getting back to the original question, about alcohol on a starship, the second part of the problem isn't just drunkenness, it's everyone who's not fully active on the crew: very pregnant women, children of all ages, teenagers, the elderly, and the otherwise incapacitated. The ship has to be livable for these people (unlike Biosphere 2), and the mission also has to survive having a respectable percentage of these people among the crew at any one time.

200:

Scotch is by definition whisky made in Scotland, and Japan's a few thousand miles away, so could no more make Scotch than they could make Chablis or Champagne.

What they can do is make a good single malt whisky.

(I have also attended a wine tasting in Kawaguchiko, near Fuji, and can attest to the fact they do make grape wines too, even if I wasn't particularly impressed.)

201:

The 1000 year colony seems a more reasonable idea, as anything with city-state mass is going to accelerate very slowly, even if you are using some sort of ion drive/high end physics method of propulsion. Given constant acceleration you could still achieve a reasonable interstellar velocity over a long time (which means they would have to deccelate a bit to orbit a useful planet, I assume). Having a destination in mind would be terrible important for planning purposes, although if done right this colony ship could be self sustaining indefinetly, presuming continued energy inputs available.

Also, I'm from the US, our Congressional budget process hasn't been terribly functional (or credible)for some time, sadly.

202:

I'd love to hear the brewing stories from the International Space Station. The CO2 generation might be an issue, but you KNOW they've got to brew up there whether or not they admit it.

203:

They'll be wanting coffee as well.

204:

Okay all you guys are going to think I am crazy but Amrut Single Malt whisky from India is very nice for the price. I actually perfer it to the Yamazaki 10 year old I have tried. Give it a go if you are curious. You might thank me.

205:

"They'll be wanting coffee as well."

Damn right they will. Coffee would be difficult. Maybe tea?

206:

I'll keep an eye open for it. But I'm still trying to find a bottle of Swhisky - yes, Swiss Whiskey from Valais.

207:

The various biosphere / soil threads are off base for "minimal case". We could do beer on the International Space Station now; there is hydroponic wheat and hops already demonstrated in sealed CELSS ground system simulations.

Nobody is sure how many organisms you need for really long term biodiversity. It's not clear what you'd want the seed bank to look like, for example. But the life support for the trip? ... Can do now, for various definitions of "now" (breadboard to production long-duration equipment conversions, etc).

208:

This is true - I was using Scotch as a short hand for good single malt whisky made as they make it in Scotland as distinct from premium whiskies made using other methods, as the Japanese whisky industry seems to have modelled itself on the Scotch whisky industry.

Moet et Chandon have an analogous issue with Green Point.

209:

Daniel said "I was using Scotch as a short hand for good single malt whisky ..."

In Scotland I understand they talk about 'Scotch' when referring to the blends, and 'Malt' when referring to "single malt whisky" (presumably whether or not it's good).

I've certainly had some good Japanese malt whisky - Suntory was it, and another one who's name escapes me. This was in a pub and they were £3+ and £7+ or so a measure - OUCH!

210:

This may be related to Zero-G sex.

On the one hand, nobody admits anything, but men and women have been up there together. Even a married couple, if I recall right.

On the other hand, there's a need for a little privacy. The ISS might be big enough to allow an "everybody knows, but nobody needs look". The Shuttle, you might have a married couple getting a bit friendly, but there's no privacy.

211:

Not to mention the prolific CCTV observation on the ISS. IIRC the couple that went up were asked about this at a press conference and replied by revealing that on the mission if you reached out with both arms you were likely to touch quite a few people.

212:

From an actual Scot:-
Scotch - Any whisky distilled and matured in Scotland.
Single Malt - The product of a single distillery.
Blend - A mix of Single Malts and sometimes grain whisky, normally mixed before maturation.

Anyone who gets low enough natural air temperatures (Scotland's +20C in Summer is "too warm") can make a Single Malt.

213:

paws4thot has the right of it. "Scotch" can be any old crap, including absolute gutrot whisky that's only fit for mixing with Irn Bru and hoping for the best, as long as it's at least 3 years old and made in Scotland.

214:

Despite the foregoing, Single Malt is no guarantee of quality; the best blends are actually preferable to the worst Single Malts. Right?

BTW, I prefer my Irn Bru in a separate glass, as a chaser.

215:

Swiss Whiskey. That sounds interesting. I will keep my eyes open.

216:

It's a mater of subjective taste, but I have to concede to preferring Famous Grouse to the bottom-end Glenmorangie or Glenfiddich.

Since the best blends are a bunch of different malts put together, it's to be expected that the blend is probably better balanced at least than any of its individual constituents. The worst blends ... well, I will not touch Teachers or Bells or Jonny Walker.

My least favourite whiskey is Jack Daniels. It has totally the wrong balance for my palette, and I have to be fairly drunk to even have a go at it these days - the last such occasion being in '96 in a Memphis strip club.

217:

I saw Swiss Whiskey once in a shop window in (IIRC) the old town of Zurich several years ago. I've not seen it since, despite keeping my eyes open, and I suspect it may be as difficult to get hold of as the French Whisky. (The one shop I know selling the latter is in Gare De L'Est in Paris, a shop specialising in the products of Alsace Lorraine.)

218:

Similarly, with notes:-
1) I presume you mean normal Bell's, not Bell's Islander, which uses only malts from the Western Isles? I first tried Islander in a market research session, and it has distinct notes of Islay, but not of a specific Islay Malt.
2) I have never been to Memphis!

219:

I should have specified that I meant the mass market blends, yes. I'm aware that the distilleries in question may well have premium blends that are considerably better.

As for Memphis, it was a stag night. Not mine, I hasten to add, but I will note that only three of us lasted to the end, all three of us Brits, and two of us had flown out from London that morning. Or rather, the previous morning by the time we finished.

220:

Not quite.

A blend can be a mix of malts, or be a mixture of malt and grain whisky - that is, whisky made with a grain other than malted barley.

There's definitely not a hierarchy of single malt > blend. They're different things, is all.

I have a taste for Speyside malts because I grew up near there and my dad always had a couple in his drinks cabinet (Strathisla and Aberlour being the most usual) but there you go. A good malt has a complex flavour that you learn to appreciate, just like so many fine things. I started learning very young.

221:

I'm going to stick my neck out and try to answer the question. Trust me, I'm a botanist :-)

But it'll take 2 or 3 posts and some sums. And some heroic assumptions to make things easy. So as soon as this pub closes and I get back to my laptop I'll give it a bash.

But first the assumptions to make things easy. I'll pretend that it is possible to maintain a closed pseudo-natural system with a limited number of organisms, with gardening-style human interventions. And I'll assume that the people on the ship are living "normal" lives - they aren't hibernating, and they are having kids in the normal way, for example.

Minimum number of species for real beer and real bread is barley or some other grain, hops (or other herbs for flavour), two species of yeast (one for ale and bread, the other for lager), at least two species of mycorhizal symbiotes, a nitrogen-fixing organism - either another plant with bacterial symbiotes or else a bacterial culture - three or four fungi to rot down dead plant material. The important ones are the fungi.

But how much of each and how much supporting infrastructure? That's the fun part. Numbers soon.

It would be nice to have cheese and onions with my bread and beer....

222:

Hi Ken,

You can probably do without the AM fungi, unless hops are obligately AM. Not all grain cultivars are mycorrhizal, and modern cultivars that are bred to be highly responsive to fertilizer typically are non-mycorrhizal.

Similarly, you can substitute a wet Zimmermann process reactor (think autoclave with higher temperatures, pressures, and added oxygen for that extra something) if you want a mechanical way of breaking waste down. I'm not terribly fond of this method, partially because I suspect the effluent gases and ash are harder to distill than the old space colony buffs thought, and (mostly) because I've worked with big autoclaves, and their failure modes tend to be spectacular.

Still, the bottom line is you can get away with less than you think, as an absolute minimum. If you want to go 100% biological, then it can get more complicated. A goat, some rabbits, or some termites might speed up decomposition quite a bit.

223:

Yes but we want mycorrhizae to help us colonise and terraform our anticipated New Earth. I said "heroic assumptions"! And I'm a biologist so I want as much as possible to be biological. In fact I think we should aim to use bacterial reactors to synthesise the chemicals and materials we need to make things.

And we want numbers, so the first one is "how many people do we need to support?"

224:

How many people do we need to support?

For colonisation, as many as possible - because we want as wide a sample of human genetic variation as we can get so the colonists can have as good a chance as possible of adapting to new living conditions.

For travelling, as few as possible, to save mass.

For the travellers, as many as needed to produce a biologically sustainable community. Its a Pitcairn Island situation. There need to be enough founders to avoid genetic drift producing an unpleasantly inbred descendant population.

Of course there are all sorts of tricky ways out, like frozen sperm banks to reboot genetic diversity from a very homozygous set of travellers. But if we are assuming normal human lifestyles, we want more than that. Also one thing that peopel are likely to do is behave in such a way that they maximise their own share of the genetic descent. Can we enforce a sitation where whoever happens to be in the last generation of the crew, centuries in the future, voluntarily give up the ability to beget their own children for someone else's out of a freezer? I wouldn't bet on it.

A thousand-year journey is going to involve 25-40 human generations. 20 generations is enough to produce complete genetic mixing in any imaginable colonist party. In other words all of the final generation will be descended from all of the founders who have any surviving descendents. You have about a million genetic lineages going back 20 generations - so the chances are that everyone who arrives will be descended from everyone who departed multiple times.

What you really want to avoid is inheriting the same deleterious variant of any gene in two copies from the same ancestor. Make a wild assumption that the average person has about ten "bad" genes. To have a one percent or lower chance of inheriting two copies of any one of them from the same ancestor you need betwen 100 and 1000 ancestors.

If the average person lives to 80, and everyone has two children - which is what you need for a steady state population - each 100 ancestors implies 4-500 individuals, including children and those over breeding age. So a robust generation ship wants somewhere between 400 and 5,000 crew. A big number!

225:

Ken: For the travellers, as many as needed to produce a biologically sustainable community. Its a Pitcairn Island situation. There need to be enough founders to avoid genetic drift producing an unpleasantly inbred descendant population.

That's the wrong answer, because it completely ignores the extended phenotype. We need as many humans as it takes to maintain the generation ship in flight. This number converges with the number it takes to sustain a civilization dedicated to building and launching a generation ship. Note: not a civilization that builds and launches one as one of a number of concurrent apex activities, but as a primary objective, as central to their economic and political lives as maintaining a military capability would be to the USA today.

Given the need -- as part of this package -- to educate sufficient numbers of the next generation to a level capable of performing this task, and the tendency of humans to revert towards the norm, I reckon we're looking at minimum one million PAX, and quite possibly 5-100 million. In other words, it's a city state in space, not a "ship".

So genetic diversity among the humans is probably the least of your worries ...

226:

Scotland and the people of Scotland enjoy a pretty decent standard of living by historical standards.

The dry surface area of Scotland is 79 thousand km2 approximately. This hosts some 5 million people; a population density of about 65 people per km2.

I’d adjust that down by a factor of 3 to reflect the view that if we all lived like people in the West do we’d need three planets. (This is pretty fuzzy thinking, there are a lot of other factors at play that don’t directly apply to a NSFNAAS, I’m trying to build in a significant margin of error whilst doing some Fermi predictions.)

I suggest, in order to put a nation-state in space of the size, wealth and complexity of Scotland we would need approximately 236 thousand km2.

In a vessel that was a torus I think we would need a ring with a diameter of 376km, a height or length of 2km and thickness of 1 km thick with that thickness made up of 100 decks each 10 metres high.

That should give us plenty of room for all matter of traditional Scottish activities along with lots of volume for the process carried out by natural capital such as water and air recycling.

I estimate the mass of this city-state in space at 360 billion tonnes, assuming most of it taken up with air.

You could cram us into a smaller space by using artificial process for things like growing food and air purification but I think this would be a less pleasant place to live and also we already know that natural process work and work well over a long period. (Granted less proven that we can put them in a bottle, even a very large one.

With that acreage I reckon we could grow 136 million tonnes of barley. At 20kg of barley per gallon of beer I reckon that gives us 489 billion litres of beer per year, or about 200 thousand pints per man, woman and child per year.

227:

Good point. However, unless we get the number down to Ken's range, we're never going to see a starship.

I've forgotten how much it was to send humans on the shuttle into space: $100 million per person? We're looking at suborbital space tourism in the $100,000 range, so currently, it takes at least $1 million, and probably more like $10 million or more to put one person into LEO.

Just moving 5-100 million people using current methods would take more than global production. That's without the materials to support them. It's a non-starter.

Conversely, we know we can move agriculture pretty effectively with 50-100 people, because that's how Polynesian settlement worked. They only needed one person to know how to build a boat, so few islands entirely lost that technology, either.

As for starships, the only hope of down-scaling the population is to make the technology "fractal," scaling in a way that minimizes the number of esoteric specialties and maximizes the number of functions an average person can learn and perform.

As others have noted, the simplest way to do this is to create a living starship (either as an organism or ecosystem), leave key steps of its reproductive cycle(s) in human hands, and make sure it loves us. I don't know how to do this either, but learning how to grow a functioning screwdriver and a mile of insulated wire from bacterial cultures might be a really good place to start.

228:

No, Scotch is any whisky made in Scotland and matured in Scotland for at least three years in accordance with the Scotch Whisky Regulations 2009.

I don’t know about the rest of Scotland but those Scots and honoured foreign guests offered a drink in my home in Edinburgh are offered, inter alia, “whisky” and if they would like a whisky are offered a choice of whiskies by named or numbered distillery, brand or region or intensity depending on how knowledgeable I think they are.

I have a blend that I blended myself which I think is very nearly the perfect whisky (for me). I think one can exagerate the difference in quality between blends and single malts or vatted malts).

229:

At some point we are going to have to invoke a speculative technology. However I think for the purpose of the thought experiment it's more interesting and realistic to speculate access to space being cheap (as well as space manufacturing). Reason being that designing and building a cheap, reusable SSTO vehicle seems less of a stretch than designing and building technology allowing artificial ecologies or labour amplification in the form of better education/management/AI etc.

230:

The dry surface area of Scotland is 79 thousand km2 approximately. This hosts some 5 million people; a population density of about 65 people per km2.

Bad analogy.

Firstly, 70% of the population of Scotland lives in 5-10% of the surface area -- the lowland central belt, running east-west from Edinburgh to Glasgow.

Secondly, of the remaining 30% of the population, most live in a handful of medium-sized cities.

The Scottish Highlands are virtually uninhabited -- well, they're inhabited for American rural values of inhabited -- because they're crinkle-cut. The mountains aren't tall, but by golly they've got a lot of very steep slopes, and there's a lot of them.

Probably a better spatial analogy for a self-propelled spacegoing city state would be something of the same urban density as Kowloon, plus high-intensity agriculture to support that (plus margin of error).

231:

Some BOTE calculations suggest that at current energy prices, even given a space elevator with a 100% efficient climber motor for raising freight, it'd cost around US $30,000 per person from surface to GEO.

So my assumption is that any space colony will be a climax development of prior industrial expansion into space (once it becomes cheaper and more convenient to service personnel downtime on site than by shipping them home), and that any such starship will be a climax development of a successful space colony system that has become effectively economically autonomous from earth.

The time frame for this to occur is barely measured in single-digit centuries, unless we make some technology breakthroughs first (of the kind that I keep banging on about us not being able to take for granted).

232:

Chasing SSTO strikes me as a fool's errand. I'm more optimistic about the idea of cable-based systems such as orbital pinwheels -- not a full-scale space elevator, but a gizmo that can supply a butt-load of kinetic energy to a sub-orbital payload to boost it into orbit, and recover the energy using high-specific-impulse thrusters that would be useless for getting off the ground. (Or use an electrified coil moving through the Earth's magnetic field for reboost -- presumably solar or nuclear powered.)

Using a 300-1000km tether is a tall order from where we're standing now, but probably doesn't require new materials science (unlike a full-scale space elevator) and it gets you a chance to use motors an order of magnitude more efficient than nuclear thermal rockets without the associated failure modes.

Alas, tether experiments are still in their infancy; either on a tiny scale, or Too Big To Fail (then they failed, dangerously and messily).

233:

Yes and no. I'll be amazed if we see the cost of space shots come down to the cost of commercial aviation. The problem with SSTO is that, structurally, it's an eggshell filled with gasoline. It's easier to launch something and bring it down empty (though no one has ever done that successfully), but the reverse (bringing a ship down full of fuel and then relaunching it) is a real pain. Most of the weight has to be fuel, and keeping it from igniting on entry is an interesting challenge to say the least--it's the same problem as making a eggshell that is not only non-flammable, but which doesn't transfer heat to the interior. It's simpler to land an empty rocket and a fuel manufacturer, which is what all the manned Mars missions seem to be predicated on.

SSTO is just another speculative technology, I'm afraid, right there with the beanstalks.

This is just another scaling issue. If only city-ships are workable, then getting people off the Earth becomes the bottleneck. Getting through the bottleneck by reducing the city-ship to a village-ship requires similar breakthroughs in speculative design.

That's really the ultimate problem with starships and even space colonization: they require massive, civilization-changing innovations simply to exist, they appear to cost a sizable fraction of Earth's economic and biosphere output (each), and they appear to have no benefit for the Earthlings who are creating all this technology and economic surplus to make them possible. All of this may change, but I suspect a lot of us have figured it out already (at least subconsciously) which is why talking about booze is more interesting.

234:

No coffee and no tea means no ship for me.

235:

So long as the dude running the pinwheel gets to wear a fedora, and everyone surviving a ride on one gets to be called a whippersnapper, I'm there.

236:

I used SSTO orbit flippantly. Something like HASTOLS (http://www.spaceelevator.com/docs/355Bogar.pdf, sorry I can't do the proper hyperlinking!) or a space elevator would be great. Though the biggest safety problem with a space elevator is what happens if the cable breaks for whatever reason (including sabotage). Then you get tens of thousands of kilometres of material smashing all around the equator at extremely high speed.

237:

Charlie writes:

That's the wrong answer, because it completely ignores the extended phenotype. We need as many humans as it takes to maintain the generation ship in flight. This number converges with the number it takes to sustain a civilization dedicated to building and launching a generation ship. Note: not a civilization that builds and launches one as one of a number of concurrent apex activities, but as a primary objective, as central to their economic and political lives as maintaining a military capability would be to the USA today.

Given the need -- as part of this package -- to educate sufficient numbers of the next generation to a level capable of performing this task, and the tendency of humans to revert towards the norm, I reckon we're looking at minimum one million PAX, and quite possibly 5-100 million. In other words, it's a city state in space, not a "ship".

So genetic diversity among the humans is probably the least of your worries ...

I think that depends a lot on how many generations we're talking about, and how complicated "maintain the starship" ends up being.

The totality of "manufacture a new starship" is probably impractical. And unnecessary. That's what margins and redundancy are for.

Our civilizations build things - civil engineering projects, some factories - that last for generations now. They don't need total reconstruction. They need maintenance.

The crew needs to be big enough that subsequent generations aren't all dedicated 80 hr/wk astronaut workload types, yes. And not on the average as bright, or healthy, etc. The question is, what level of person can handle what level of task.

I.e., do you need a hundred IP 165+ geniuses to do ongoing repairs, or will it suffice to have a few IQ 120+ techs / engineers, a few smart leaders, and a bunch of average workers to keep replacing pipe fittings and wiring and bearings on things?

Design-for-maintenance, design-for-durability, remote support (even with years or decades of round trip communications lag), etc. all play into this.

I am greatly regretting not making the time to go to the conference.

238:

Charlie can certainly speak for himself, but a starfaring culture doesn't get that far if it loses its ability to build a starship. There are examples from Easter Island, Micronesia, and Polar Eskimos (as well as Pitcairn) of societies that lost not only their boats, but their ability to make boats. Their histories are (for the most part) unpleasant.

Mind you, I disagree about the number of people needed to build a starship (especially if those people are graduates of the Hogwarts School of Speculative Engineering), but it's an important point. A single, one-way trip to another solar system ain't worth the cost. If we're going to disperse Gaia across the local galaxy, we really should do it properly.

239:
Charlie can certainly speak for himself, but a starfaring culture doesn't get that far if it loses its ability to build a starship. There are examples from Easter Island, Micronesia, and Polar Eskimos (as well as Pitcairn) of societies that lost not only their boats, but their ability to make boats. Their histories are (for the most part) unpleasant.
Mind you, I disagree about the number of people needed to build a starship (especially if those people are graduates of the Hogwarts School of Speculative Engineering), but it's an important point. A single, one-way trip to another solar system ain't worth the cost. If we're going to disperse Gaia across the local galaxy, we really should do it properly.

There are plenty of colony expeditions that succeeded that didn't include full shipbuilding tool or skill sets.

The question isn't "will the colony be able to propagate", it's "can the colony propagate RIGHT AWAY".

There's a world of difference between a one-way science mission, not intentionally enough people to clearly succeed as a viable long term colony, and a colony mission that will take generations to take root and rebuild full technological civilization in all its glory.

I suspect that sending multiple minimum-credible sized colonies is likely to succeed over any reasonable time frame (from start of program) faster than waiting until you can send a full sized city-colony in one giant toss.

Some will fail, but any that succeed can grow exponentially as humanity is wont to do, and getting someone there earlier is more likely to succeed faster overall.

240:

the biggest safety problem with a space elevator is what happens if the cable breaks for whatever reason (including sabotage). Then you get tens of thousands of kilometres of material smashing all around the equator

No you don't. The beauty of it is that the segment at GEO is already in Earth orbit, and most designs include a counterweight out beyond GEO to hold the elevator under tension. If a break occurs at, say, 200km up, then the bottom 200km falls ... but everything above it actually rises because it's dangling from a massive body in orbit. Build the thing on the eastern equatorial coast of a land mass adjacent to a convenient ocean and you can probably ditch the first couple of thousand kilometres of cable without major problems, and everything above there takes care of itself.

There are other solutions involving pyrotechnic cutting charges for breaks that occur at an inconvenient height (say, 10,000km up). If you sever the cable at 1-1000km, the upper segments sail off into a variety of orbits or ballistic trajectories that re-enter the atmosphere in small chunks and burn up.

Of course, this emphasizes the need for passenger-carrying climbers to be equipped with heat shields, parachutes, and distress beacons ... just in case!

241:

I think that depends a lot on how many generations we're talking about, and how complicated "maintain the starship" ends up being.

The totality of "manufacture a new starship" is probably impractical. And unnecessary. That's what margins and redundancy are for.

You missed my rant on why the term "starship" is a mistake and we should stop using it, right?

Briefly: there is no "there" at the other end of an interstellar voyage. The probability of us finding an earthlike planet with an oxygenated atmosphere where we can live without life support anywhere within 50 light years of here is low; even within 5000 light years it's not high. In the absence of some kind of magic space drive that allows extremely rapid travel, we have a problem. We can send unmanned probes, sure -- but if we send people, they are either going to have to establish an entirely self-sufficient colony at the far end, or re-fuel and re-tool for a return to Earth, or ... die.

I discount the utility of multi-generation suicide missions because, while the first crew might be willing, their descendants are more likely to say "fuck that" (to the people who stranded them) and devote their energy to trying to survive instead of conducting the mission.

So we're left with the requirement for a manned generation vehicle to be essentially a self-sufficient space colony with a motor on one end. (Probably following along behind unmanned probes.)

242:

A more succinct way of saying it: any multi-generational human interstellar mission needs to be isomorphic with a self-sustaining space colony (plus propulsion tech) if it is to succeed.

(This does not rule out the practicality of unmanned probes, or -- if we have workable deep sleep/cryogenics -- a crewed probe where the crew, having accomplished the mission, dig a hole in an asteroid, enter cryonic suspension inside it, and wait for a colony to turn up in a few thousand years.)

243:

I wonder if it's really easier to live in an asteroid belt than on a world with a non-toxic atmosphere and liquid water.

244:

If there's water and the atmosphere is non-toxic and there are no pre-existing biota to which you are allergic or to which you taste crunchy with fries then the planetary surface is going to be more hospitable, probably. There are any number of gotchas within these constraints, however. (Such as large moons raising 70 metre tides every 6-8 hours ... as on Earth, 3-4Gya ago. Or Robert Charles Wilson's fun speculation in "Bios": any planet with a biosphere is so friendly that if you step outside without protection you die of massive anaphylactic shock within half an hour.)

If the atmosphere's toxic or the temperature range is wrong for three phases of water (vapour/liquid/solid) then an asteroid belt may well be more hospitable.

245:

There are two real problems here.

One is that our definition of a non-toxic atmosphere is also far from chemical equilibrium. It only occurs when life is monkeying around with biogeochemical cycles. Chemical equilibrium is a carbon dioxide atmosphere.

That's the second problem: if the atmosphere is non-toxic, then there's a biosphere. It can be non-toxic in two ways: either it uses the same chemicals we do (DNA, RNA, amino acids, all the same chirality) or it does not.

In the first case, we have to worry quite a lot about diseases. And allergies. In the second case, we have to do massive biogeochemical fiddling to turn bits of the alien biosphere into things we can eat, and we still have issues with allergies and toxicity.

Either way, you're unlikely to find a planet where the atmosphere is non-toxic, the local biota are edible, and you're not on the menu in some fashion.

Doesn't mean we can't settle a world with an oxygen atmosphere. However, if you want to keep your Gaian identity pure, you need to settle an asteroid or similar where you build your biosphere from raw, non-living materials. Otherwise, you're becoming part of an alien biosphere, which means that you're going to have trouble interacting with pure Gaianists after you settle that planet.

246:

No, non-toxic in this case doesn't mean "supports respiration", but "if injected into my breathing mix at 10%, I don't die/suffer". So, a 100% nitrogen atmosphere would pass.
Ammonia, hydrogen sulfide and carbon dioxide are all toxic in large amounts.

Would a world with a carbon dioxide and nitrogen atmosphere be better than an asteroid belt? Would a world of the earth's mass with whatever atmosphere we'd expect be more hospitable?

247:

Time for the attempt at an answer. Sorry for big post but I'm thinking aloud... How much food production is needed to sustain those people? And how much extra would be needed to give them all some nice beer each day?
(Though of course we all know the *real* problems of large motile space habitats would be cooling)

My guess is you need about 100 square metres of illuminated surface to feed each person, a hectare per thousand. And adding in the beer almost doubles that.

Open air agriculture that has to contend with climate and winter and so on is rather more extensive than that. In real life the area of cropland required to feed one person is about 4-5000 square metres in the USA, about 700-1000 in much of western Europe & China, and down to 500 or less in some high-intensity tropical areas - the world average is about 2300. So I'm assuming the spacefarers will be able to design systems about five times more intensive than the average Javanese farmer.

Consider the food yields of normal agriculture. Because we can probably do better than that so its an plauisble minimum. Imagine a space colony with large spaces subject to gravity or spin with some sort of soil or soil substitute on the floor and bright lights in the ceiling (or suitable mirrors taking light from the sun)

An ordinary English farm averages about 5-6 tons of barley per growing season per hectare. Wheat yields are higher in our temperate climate, and in tropical climates maize and rice yields can be much higher, over twenty tons a hectare. So barley ought to be able to manage 10 under optimised conditions. With a completely controlled climate we ought to be able to use fast-growing varieties to crop three seasons in a year - say a 120-day cycle. So assume ten tons of barley or wheat per hectare per season. That's a kilo of grain from every square metre every 120 days.

How much of that do we need to grow? A nutrionally adequate diet for one sedentary adult might include about 400g of grains, 400g of green vegetables or fruit, 100g of pulses or nuts and perhaps 50g of some high-fat food (might also be seeds or nuts). So that's 48 kilos of grain in our 120-day season. So each spacedweller uses 48 square metres of growing surface for grain, the size of a very large living room. The leafy veg will typically take up much less space than grain because you can do continuous cropping of various sorts, but beans and peas have only about 1/3 the yield of grains at best - so lets do some handwaving and say another 48m2 for the veg. Add in a little space for fruits and nuts and herbs and spices and we can feed one person on 100 square metres of floor area in a controlled climate using gardening techniques.

Where does the light energy come for all this? If we can build starships we can get light or electricity from somewhere. If we have to we can use onboard nuclear reactors, Dumping the heat into space is left as an excerise for the physicist reader :-)

So a crew of 1,000 are going to want 100,000 square metres of growing surface for a sustainable, adequate, and varied diet. A hectare field for every thousand.

How much will beer add to that? Someone suggested four pints per day each - about 2 and a quarter litres. So our thousand crew will want going on 300,000 litres in 120 days. Depending on strength that would require 10 to 20 tons of malt. Another hectare. Hops are perennial climbers - have them grow up the walls. You ought to be able to get ten kilos of flowers from one large mature plant. That's enough for a few thousand pints. So the good news is that we won't need to grow *that* many hops. Still need a few hundred containers to put them all in though. And the beer takes up as much space as we need for food production.

A waste? Probably not - would you want to risk your life, all your descendents, and the future of the human species on a project that *didn't* have at least 100% redundancy in its main systems? I hope not. Which is one reason this is a "trick question" of course, Whether or not our spacedwellers want to brew real ale, the resources and systems that would allow them to might also be used to do all sorts of other things that we can't predict they wll need to do.

How much kit does the brewing need? Quite a lot if you use traditional methods, and more for lager than for real ale. It typcially take 60 days to mature seeds before malting, so that's 5 tons in a grain store for every thousand crew. Malting takes 4-7 days, then kilning a few hours. A microbrewery for those thousand rather heavy drinkers would have to mash over 2000 litres a day - one large vessel. Then the same for the brew kettle. Fermentation is 4-14 days in a different vessel. Then either lagering or secondarty fermentation in kegs (or whatever container you are going to pour the drink from) for anything from 4 to 40 days (high quality lagers and some specialist strong ales can be up to a year)

So decent beer for a thousand keen drinkers brewed by traditional methods would require a grain store about the size of a typical room in a house, then a mash room of the same sort of size or larger, and a kiln, then two or three odd-shaped vessels capable of holding more the two cubic metres each then maybe a dozen fermenters of the same size, then a place to store the equivalent of 500-1000 kegs of beer. (Not that you would be likely to use metal kegs on a spaceship - inflatable containers from some bacterially synthesised polymer might be better!) And you are storing over 100 tons of water in that system. But then you have got to keep a buffer for the water cycle somewhere - why not use beer?


And how much other stuff are we hauling on order to eat and drink?

Each of those kilos of grain, if from a dwarf variety, leaves behind about 1.5 kilos dryweight of plant material that needs to be composted and returned to the soil - along with human waste and lots else. Last seasons compost will still be around rotting down. The total mass of other living organisms in natural soil is typically about the same as that in the plants growing in it - give or take several orders of magnitude for every vegetation type from semi-desert to peat-bog - and most of that is microorganisms and invertebrates. We'll attempt to exclude the invertebrates - the bee discussion showed us why we don't want large numbers of meiofauna (posh word for what primary schools call "minibeasts") flying free. So about a kilo of bacteria and fungi are in the soil or the composter rotting away for each kilo of grain. And they are respiring. Which would be a waste in an open system, but isn't in a closed system, because all their stuff can be recovered and used by the humans. Think of it as a self-maintaining store of spare nutrients.

And each kilo of grain is supported by a system containing about 3 kilos dry-weight of organic material, - which in life is 70% water. And, the most wasteful part of all, perhaps a few centimetres of soil substitute, which itself contains perhaps 10 kilos of water a square metre.

In gardening-style cultivation each hectare of floorspace producing perhaps ten tons of grain per season is going to be carrying a "standing crop" of maybe a hundred tons of compost and microorganisms and 500 or more tons of soil substutute and water. Which is where hydroponics and aquaponics comes in. Discarding soil altogether doesn't win you as much growing time as is sometimes made out, but it does save a lot of mass!

On the other hand, maybe its not a problem. If the "soil" is itself made of material with multiple purposes that you have anyway, why not store it in plain sight? None of this stuff is leaking into space (we hope). An exploratory space mission might not want to take along thousands of tons of crushed rock, or vermiculite, or urethane sponge, or woodchips, or dried peat, or damp newspaper, or any of the other things used to make artificial soil, But an isolated space habitat might have need of some of that stuff one day - and if you are storing it why not use it? Out there in the dark heavy minerals will be hard to come by. Lightweight organics much easier to find. We think space is short of water and air (especially nitrogen) but really it is much more short of iron and copper and tin.

As Charlie is saying the idea of a super-space mission on this scale is not really on. If at some time in the future large numbers of people get used to living in space, then maybe some of them will move a bit further and further out and one century or other someone might find themselves nearer to some other star than to the Sun. But will that matter to them? By then they will have lived in space longer than we have had an industrial civilisation. Maybe longer than we have had an agricultural civilisation.

Who knows, perhaps the aliens are here already? Out in the Oort cloud somewhere. Drifting around the galaxy in short generation-ship hops of a few light days at a time, pausing for centuries to exploit small comet-like objects, taking thousands of generations to go from star system to star system, not so much surging forward as diffusing through the interstellar spaces.

And we never hear them talking to each other because they do it in short tight-beam directional messages from comet to comet, habitat to habitat, beacon to beacon, using multiply redundant decentralised store and forward systems to shift very small messages around. The communications system of the future is Usenet :-)


248:

There are other candidates for low-cost surface to LEO or even GEO transport:

  • Catapult launcher (maglev, railgun, or coilgun equivalent). Probably a humongous upfront cost to build a launch rail that's at least a couple of hundred kilometers long (so the acceleration doesn't turn the passengers into strawberry jam) in places where construction isn't cheap or easy (you'd like the business end to be as high as possible to cut down on air resistance, but that means building large structures in mountainous terrain).

  • Laser launcher. Requires high-energy (not necessarily high-intensity) lasers with relatively high pulse rep rates (a couple of hundred pps in some designs) or even CW output. Note that the lasers could be used as ground to space weapons, which might cause a certain amount of paranoia among those space-going nations not building the lasers.

  • Lofstrom Launch Loop. The problem of real-time control of the loop sections to prevent instability hasn't been solved yet, and running the loop up to speed requires a lot of power. Also, dumping the energy of the loop in case of catastrophic failure will require a good-sized lake in the right place, and you only get to use the lake once, after which it's vaporized.

  • 249:
    Briefly: there is no "there" at the other end of an interstellar voyage. The probability of us finding an earthlike planet with an oxygenated atmosphere where we can live without life support anywhere within 50 light years of here is low; even within 5000 light years it's not high. In the absence of some kind of magic space drive that allows extremely rapid travel, we have a problem. We can send unmanned probes, sure -- but if we send people, they are either going to have to establish an entirely self-sufficient colony at the far end, or re-fuel and re-tool for a return to Earth, or ... die.

    There's a "there" there, or we wouldn't be going. Hanging out in space can be accomplished without spending energy to depart the solar system (or earth's general vicinity).

    At the very least, there's concentrated energy (a star). For us to bother sending people, it should have at least useful mass (comets, asteroids). Likely it has planets, based on current discovery trends.

    It doesn't have to be "another earth". Mars would do. Venus with a bit less heat and pressure would do. Several jovian moons minus the radiation belts would do. Several large asteroids will, in a pinch, do.

    It's just a matter of simplifying the colony life support and growth problem, from "scraping asteroid dust to generate a new ship".

    And, to be blunt, it's not "generate a new interstellar ship", it's "keep this colony in this new system going and growing". The difficulty in energy and capital infrastructure of launching starships means that it's highly unlikely that colony ships will be in any position to "turn around".

    The "or they die!" you're trumpeting is reality, and they need to know it (and everyone else does, too) before they get moving on the way there. Barring antimatter or warp physics in large quantities, they are stuck, and either thrive, survive, or die off. "Die off" may be voluntary and slow rather than abrupt (choosing not to reproduce if there isn't enough viable material to colonize at the far end), or may be abrupt (see any number of colonization disasters in human history).

    I know where you are coming from. But it's a unnecessarily risk-averse way of looking at it. Civilizations that refuse to travel in interstellar space until they can fly eternally self-sufficient cities between stars are likely to be grossly out-expanded by civilizations that will throw credible but cut-down fast small-population colony lightsails (or whatever) to every world they can reach as fast as they can, and accept that some of those will fail. You need to look at the target systems first - big TPF and similar system imaging to target resource-rich stars, etc. But if a system has resources, and you can go, you go. You may die, or some number of you may die, but if it's viable then someone will succeed. The risks don't grossly exceed those of merely living in space to start with.

    250:

    Ammonia, hydrogen sulfide and carbon dioxide are all toxic in large amounts.

    Incorrect.

    Going by your 10% criterion ...

    CO2 at 10% is toxic: it'd cause dizziness, headaches, hearing/visual disturbance, and unconsciousness to death in under an hour.

    H2S at 10% will kill you stone dead in well under a minute -- the stuff is more toxic than hydrogen cyanide. Interestingly, at 10% you won't smell it; it'll completely overload your nasal receptors. Just 1000 ppm -- around 0.1% in air -- is enough to cause immediate collapse with loss of breathing after a single inhalation.

    Ammonia at 10% ... well, the limit for immediate danger to health or life is a concentration of 500 ppm, or 0.05%; it reacts with water exothermically to form ammonium hydroxide, and this would happen in the lining of your lungs (not to mention on the surface of your eyes).

    So. These "non-toxic" atmospheres really aren't. Of the three, CO2 is least likely to kill you immediately -- you get a chance to get to safety. But hydrogen sulfide kills you stone dead with the first breath, and ammonia merely burns your lungs out with the first breath.

    If I was looking for a "non-oxygenated, but relatively forgiving" off-earth atmosphere I'd go for 90% nitrogen and 10% CO2. Your "10% exposure" test then gives us enough CO2 to be noticeable and annoying but not immediately fatal, plus nitrogen (no effect unless we go over 95%, in which case there's not enough oxygen left over to support respiration). In other words, you'd notice something wrong if there was a leak, but it wouldn't kill you unless the leak was catastrophic.

    251:

    That sounds broadly right.

    A couple of additional thoughts: we're doing this in space, presumably out beyond Earth's Van Allen belts, so we're exposed to cosmic radiation. So we need radiation shielding. The best/cheapest shielding is a 10 metre thick blanket of water (or ice) around the biosphere -- quite massive, as it weighs 10 tons per square metre of shielded area on the inside. However, as we make our habitat larger, volume increases as the cube of the radius while surface area (hence mass of shielding) only increases as the square. Thus, bigger is better, because volume is cheap. (Means we can afford trees and some open spaces as well as micro-scale intensive gardening.)

    Dumping the waste heat from the metabolic cycle is indeed going to be problematic in deep space (as is dumping heat from any nuclear reactors we're running to provide lighting and/or propulsion). A human being puts out on the order of one kilowatt of heat; I wonder what the corresponding thermal output of the rest of the nominal one-human sized chunk of the biosphere is going to be? (We have composting processes, we need to include energy used in food cultivation and preparation, inefficiency in the lighting system -- although I think high-efficiency LEDs tuned for maximum efficiency in driving photosynthesis should cut into that wrt. current lighting solutions), and so on. I'd be astonished if we didn't have to put more than 10kw of power into the system to keep a 1kw human being alive, and that 10kw is eventually going to come out as low temperature thermal radiation.

    252:

    Can I just say that the Lofstrom loop gives me the heebie-jeebies? If that thing fails, you're looking at the equivalent of a decent size thermonuclear explosion's worth of energy that needs to be dumped.

    Basically, any of these launch systems look like a weapon if you squint at them wrong. As, it must be admitted, do multi-stage rockets (ICBMs). Indeed, anything capable of putting a payload into orbit can probably be re-purposed as a long range bombardment weapon. (And even sub-orbital tourist flights are going to be subject to rigorous anti-terrorism legislation. Because anything that can do Mach 5 with passengers on board makes a hell of a nasty kamikaze weapon.)

    I suspect orbital pinwheels or space elevators might just have a political-acceptability edge because (a) in event of a failure most of the energy dump occurs in Earth orbit rather than on the surface, and (b) you can keep a telescope pointed at them to ensure nobody's using them for naughty hanky-panky.

    Finally, there's one launch system we've ignored, but which looked very promising in the 1980s until Mossad assassinated its designer: Big Babylon, Gerald Bull's space gun. You can't launch humans with one (acceleration is in the high hundreds to low thousands of gees) but for uploading chunks of construction materials by the ton on a 90 minute cycle it might well be competitive with a space elevator. And if anyone could do it, Gerald Bull could have done it (the guy who ran Project HARP and designed the Titan II and Minuteman re-entry vehicles, not to mention the 20th century's greatest artillery designer).

    253:

    I looked up "ancient earth atmosphere", which claimed that the earliest atmosphere was dominated by hydrogen, nitrogen, ammonia, and carbon dioxide with significant amounts of hydrogen sulfide, but the other inner planets (currently) have atmospheres dominated by carbon dioxide.

    On earth, the ammonia was split into nitrogen and hydrogen by ultraviolet rays from the sun. So, presumably, that might not happen on a world circling a red dwarf.

    Did you know that our sun is almost as large as it can be and still last this long? The lifespan of a star like the sun is roughly inversely proportional to the cube of the mass, and we're half way through the sun's time on the main sequence. The sun couldn't be more than about 26% heavier than it is.

    If our sun is that unusually hot, that might imply something about the development of life.

    254:

    "I'd be astonished if we didn't have to put more than 10kw of power into the system to keep a 1kw human being alive, and that 10kw is eventually going to come out as low temperature thermal radiation."

    It's probably closer to 100 kw per person or more. Plants convert light to biomass at 10-20%, and humans convert food to biomass at ~10% efficiency, so that's 1-2% conversion efficiency, or 50-100 kw per person in the system.

    That's the green part of the ecosystem. I don't have numbers for running the brown (decomposer) part of the ecosystem, but we need to have that powered to recycle nutrients. It might actually run off the waste energy lost during conversion.

    As for design, I'd point out that separating the heat radiators from the ice shield appears to be a good idea. Add in a plasma shield for microdebris, and just the location of the necessary elements for a vessel or colony makes for some interesting design issues.

    255:

    Hi Ken,

    Just realized there's another number that's necessary, and that's the plants (and other organisms) needed to keep the air breathable by pumping O2 in and CO2 (and N2) out, and the ecosystem necessary to keep the water clean. I'm not sure whether everyone can breathe on 400-500 m2/human, especially since the plants and everything else respires too.

    Do you have those numbers handy, or do I have to unpack my books too?

    256:

    How about distilling it and calling the solid residue fertiliser?

    257:

    I can't remember the numbers for respiration either! Maybe in a few hours time... where did I put those plant physiology books?

    258:

    I dimly remember, probably from a previous thread, someone saying that if you can produce enough food to eat, then your oxygen problem has already been solved a long time ago. (by an order of magnitude or so, IIRC)

    But I was thinking ... since we're talking about a closed system, doesn't the the oxygen-producing and the oxygen-using sides of the equation have to equal each other, pretty much by definition? (Which still leaves the possibility open that we find ourselves in an equilibrium that doesn't have the optimal concentration of oxygen for humans to breathe, of course.)

    It seems that you might, in principle, switch that phrase around, and ask "how many CO2-producing humans/animals are required to sustain the plants' needs". Right?

    So, aren't we looking at a self-balancing system here? Say the balance shifts towards too much CO2, that would encourage plants to grow faster and produce more oxygen, and so on...

    The problems I can see would be with microorganisms using up too much oxygen, carbon being locked up, and that sort of thing; problems that it seems would be hard to scale out of by adding more plants. Or am I way off here?

    259:

    Biosphere 2 is the classic counterexample, but it's something that happens in shallow ponds every day.

    Basically, carbon in plant tissue comes out of the air, and in fact, global carbon levels drop noticeably during northern hemisphere spring, due to new plant growth. Plants under light do produce excess of oxygen over their own respiratory needs, but they take up oxygen at night, the same way we do. Remember that every aerobic life form takes in oxygen. Our atmosphere is due to a surplus of photosynthesis over respiration.

    Also, you typically have to kill the plant (or it dies) to harvest it. Your closed system with grain in it therefore has a fluctuating atmosphere: [CO2]in the air drops as a crop grows, then the carbon builds up as plants stop drawing it down and respiration brings it back up.

    Biosphere 2 had a wild ride on their first mission. [CO2] levels fluctuated wildly (600 ppm/day, 3500 ppm/year). Shallow ponds work a similar way: most of the carbon dioxide gets sucked out of the water during the day, and it gets replenished at night. There are even a few aquatic CAM plants (basically, they take in CO2 at night and store it for daylight use) that take advantage of this cycle.

    There are a number of ways to buffer the air chemistry in a space colony: make it bigger, add in plants whose primary job is to supply oxygen, add in mechanical regulators, and so forth. The fundamental problem is that the flows of elements such as carbon and oxygen (respiration, photosynthesis,etc) are large relative to the stocks (atmosphere, biomass) in the colony itself. Keeping the stocks perfectly constant is impossible, and keeping concentrations survivable is a good design challenge.

    260:

    Right. I wasn't thinking much about fluctuations. Is that really a problem though? I'll assume that you'd want to avoid seasonal variations, or that if you do want them, you'll arrange to have all seasons going at all times, in different parts of the biosphere. Same thing with harvesting; not arranging so that food comes in continuously seems like an odd choice to make, for several reasons.

    Day/night won't be as simple as that (or will it?)1. But I wonder how much buffering you'll get from the atmosphere, the numbers have gotten pretty large after all. (and when you add all that surface for growing, the volume goes up too...)

    There are a number of ways to buffer the air chemistry in a space colony: make it bigger, add in plants whose primary job is to supply oxygen

    I don't see how adding oxygen-supplying plants could help. What will they do differently from food-producing plants? (What happens at night? Or when they decompose?)

    (Hope this doesn't come off as argumentative, I'm really trying to puzzle things together here, and obviously didn't learn anywhere near enough in biology class all those years ago.)


    Note 1: Seems like one could make a case for having multiple time zones too; switching the equivalent of one enormous lamp on and off, all at once, every day, might not be ideal for your power source and electricity grid. Shifting daylight around would mean you get to hold energy consumption constant instead..

    261:

    Here are two basic numbers to remember (for the third time): "Biosphere 2 had a wild ride on their first mission. [CO2] levels fluctuated wildly (600 ppm/day, 3500 ppm/year)."

    Here's the translation: Currently [C02], which is the concentration of carbon dioxide in the year, is 389 ppm on Earth. In Biosphere 2's first mission, they experienced DAILY fluctuations of 600 ppm, and season fluctuations of up to 3500 ppm. They had high CO2 levels, and on a daily basis, they experienced a bigger swing than the concentration of CO2 in the air currently.

    If you want day/night cycles in your biosphere, you're probably going to get CO2 swings in the 500-1000 ppm magnitude. I'm assuming that at least some greenhouses will be under 24 hour light, and they can provide additional oxygen. You can also use CAM plants like prickly pears (ideally the spineless kind) to suck up CO2 in the dark and use it to photosynthesize during the day. They probably aren't going to emit oxygen during the day, however.

    As for how to balance it out, it's not an issue of seasonality so much as it is one of tracking growing cycles on all your organisms, and keeping a good accounting of how much biomass you have, where it is, and what it's doing.

    262:
    they experienced a bigger swing than the concentration of CO2 in the air currently

    They were fairly small though. What will the numbers be in a much bigger closed box? (Ken?)

    I'm assuming that at least some greenhouses will be under 24 hour light

    Ah, so that's what you meant by having extra oxygen-producing plants. Makes sense now.

    I think my "season" and your "growing cycles" are the same too.

    Hopefully there will be another Humans In Space! thread soon so we can have some more people involved, ideally with a few who've already done the necessary calculations. :-)

    263:

    Day/night won't be as simple as that (or will it?)

    We don't know. One interesting question that needs to be asked is: how much "night" do our crop plants need? I will note that the night/day duration varies throughout the year over much of Earth's surface, and in the arctic/antarctic circles there may be up to six months of darkness followed by six months of daylight.

    It's possible that some crop plants don't need night at all -- or can be tweaked to cope with 1-2 hours of reduced daylight per 24 hours, thus considerably boosting the proportion of time during which photosynthesis can operate. Or some may require roughly balanced light/dark periods. Or exhibit optimal growth at a diurnal cycle significantly different from 24 hours.

    Once you're not stuck to a big spinning sphere orbiting a gigantic point light source, these questions get rather interesting.

    264:

    In addition to the day/night cycle I've always wondered what effect not having seasons would have, on both crops and animals. How will our ecosystem work if half of the species require seasonal changes? At first we could get round the problem by saying we'll take things that don't undergo changes (e.g evergreen trees and non-migratory animals) but I'm willing to bet that somewhere in the tangled webs of ecological interactions there are a few critical species that need seasonal change.

    265:

    One issue is that some plants use seasons as a cue for things like flowering. In this case, it's the length of darkness that triggers. For plants that flower in the fall or winter (short-day plants), there are stories of security guards ruining everything by walking through a greenhouse at night with a bright flashlight. As soon as the right light hits the receptors, it resets the night-length counter.

    Some cultivars have already been bred to be day-length neutral (e.g. these receptors have been disabled and the plant still completes its life cycle) so I'm assuming that it's possible to stock a biosphere with plants that will respond appropriately to the light. Still, circadian rhythms are pretty potent and biologically very basic, so it's something else to manage in your system.

    This also gets at the question Ryan asked about seasonality. Additionally, many seeds need chilling (or a variety of other treatments, up to and including a prolonged soak in concentrated acid) to germinate. Horticulturalists fake these all the time, which is why many greenhouses have a big fridge in the head house where they prepare things.

    266:
    It's possible that some crop plants don't need night at all -- or can be tweaked to cope with 1-2 hours of reduced daylight per 24 hours

    That's more or less exactly what the time around midsummer is like here at 60 degrees north, and agriculture seems to have survived.

    Once you're not stuck to a big spinning sphere orbiting a gigantic point light source, these questions get rather interesting.

    They do... I'm beginning to think that having one single "night" and one single "day" per 24-hour period is going to cause more problems that it solves, and not just because of photosynthesis/respiration. Let's split our city state up into three or four timezones instead, and spread the load on infrastructure around too (everyone turning their kettles on at the same time, office buildings being empty for 2/3 of the day, and that sort of thing).

    A side effect would be that you'd get 3-4 somewhat separate populations, which might be both a good and a bad thing. You could perhaps move to get away from people, for example...

    267:

    ...there are stories of security guards ruining everything by walking through a greenhouse at night with a bright flashlight. As soon as the right light hits the receptors, it resets the night-length counter.

    Yes. There's a story, possibly true, about finding a singularity in the diurnal cycle control systems of mosquitoes; apparently it could be sent into chaotic behavior if the insects saw light as just the wrong time of night. It does point out that systems have odd failure modes, and some of them are completely unexpected until you step in something squishy. Alas, I'm sure we'll find more than a few of them when we try to build self-contained ecosystems, so the more work we do on the ground and in near-Earth space the better.

    Magetoo, your several-shifts idea is an interesting one; I'm not sure how it would work out in practice, but I don't know that it's been tried with a natural population and am curious how it works out.

    268:

    A side effect would be that you'd get 3-4 somewhat separate populations, which might be both a good and a bad thing. You could perhaps move to get away from people, for example...

    I doubt those populations would stay separate for long. On the contrary, I would expect quite a bit of diversity in the length of the cycle that people feel comfortable with, if it stops being forced on a 24-hour cycle by celestial mechanics. I, for one, would be happy to wake up an hour or two later than the day before, every day. I don't do it because I need to fit my schedule to working hours and shop opening times (as per xkcd#320, shifting my schedule by 4 hours a day later would actually be easier). Knowing that some people wake up like clockwork on a 24 hour cycle rather than the 26 hour cycle I prefer gives a beat frequency of roughly 2 weeks, over which I'd have moved through each of those populations and back to the first one. I suppose you could have a 2-dimensional segregation with frequency on one axis and phase on the other, but to me it makes more sense to let everybody make their own schedule regardless of where they live. Possibly driving the analogy way too far, lasers (with coherent phase and frequency) are a lot more likely to do harm at a given power level than white light (with incoherent phase and a range of frequencies).

    Also, I've heard people from the nordics claim that they get sweeter strawberries than spanish strawberries because a bit of extra light does more for the plants' average sugar production when the plant would be using sugar for respiration, because it's dark, than when the plant already has light and is already making sugar.

    269:

    Temperature matters as much for plants as light. Remember that most plants work at environmental temperature, so they respire more when it's hot. A cool system with bright lights would theoretically load up the sugars on plants that could survive it (such as apples).

    The bigger issue for a small biosphere is managing the carbon cycle. If you're growing a grain, a good chunk of your carbon is going to get locked up in those plants. Once they die, the seeds get harvested, and some of that carbon is still locked into the seeds, until they are eaten. The rest (the straw) could be composted, which locks some of the carbon into the soil, or fed to goats, in which case a lot of the carbon is farted out, some goes into the goats, and some into goat droppings. Eventually, that carbon makes its way back into the air, so plants can use it again. Depending on the release cycle, it may take days (via goat farts) to years (compost and stored seeds) to get the carbon back where the plants can use it again.

    That's the real cycle you have to manage. On Earth, the cycle's so huge that even big farms don't really perturb the local carbon cycle (nitrogen and phosphorus yes, carbon and oxygen, no). In a small biosphere, any crop is going to appreciably change elemental balances. The trick for keeping everything alive in a small biosphere is some really fun logistics. It's doable (even at Biosphere 2), but not as simple as setting up seasons, or alternating day and night cycles. You've got to measure what your compost is outgassing, measure the carbon inputs to the atmosphere from goat farms and beer bashes, and so forth.

    270:

    ISTM that everything we've been saying here in this set of threads about what it takes to send a colony to the stars points to the need for massive scale. We need large communities to ensure all the needed skills are available and that none are lost over time; we need large structures to provide radiation shielding, protection from space junk, and gravity from spin; and we need large biomes to buffer against fluctuations in atmospheric gasses and to make the logistics of managing the various chemicals of the biomass practical.

    In terms of the tropes of hard SF, we've come full circle since the 1930's when Stapledon wrote about interstellar travel using first asteroids, and then whole planets. The image of the airplane took over for a long time, because it represented the newest of technologies, and because most people just couldn't visualize the magnitude of the distances involved.1 Now that we've actually gotten off the surface of the earth, and understand just how hard that is, we have to scale up our ideas of what it will take to go the much longer distances to another solar system.

    1. When I was 9 or 10, back in the early 1950's, we had an encyclopedia called "The World Book". It had an article on space travel in which there was a diagram of the solar system, with a drawing of a DC-3 prop-driven aircraft flying from earth to each of the other planets, and the time required to make each trip at the 150 mph cruising speed of the plane.

    271:

    Looking at Ken Brown's post @247, interestingly, you need massive scale but not actually absurdly massive. He reckons that, reckoning in the vital beer, you need 200 sq m of illuminated surface per person. However, I think he's got a units problem, as he describes this as two hectares per 1,000 crew. Wikipedia sez a hectare is 10,000 sq m, so this s/b 2 ha/100 crew. The deck area of the M/V Emma Maersk is 397m*56m = 22362 sq m or 2.23 ha. (Alternatively, Trafalgar Square is roughly a hectare.)

    Obviously, in a space ship rather than a ship ship, you can do clever things like vertical farming if you arrange the lighting right. The Emma is 30 metres deep from the deck to the keel, not counting the space in the centrecastle superstructure. So we could use the first few metres of depth to double the "land" area and get to a crew of 200. Kicking it up a notch, the biggest ship ever, SS Seawise Giant would give you 3.15 ha and the same reckoning gives you a crew of 310 or thereabouts.

    So, something the size of a really big ship. Perhaps part of the problem is that we think of starships as star-planes or star-rockets rather than at least ship-sized objects.

    The problem here is that you'll need more than 300 people, but then I'm sure we can think of something SFnal to do involving a relatively small crew and long duration, or else there's the generation fleet concept, as it might be much easier from an engineering point of view to build a lot of Emmas in orbit than one psuedo-moon.

    272:

    Of course not.
    That's what good strong English cider is for.
    :-)

    273:

    Or proper lager; see Charlie's reference to the Reinheitsgebot.

    274:

    I guess you could use algae blooms as short term carbon sinks and forests as long term storage. If your CO2 levels are trending high, increase lighting and aereation to your algae farms to suck up the excess CO2. If your CO2 levels are trending low, just burn some forest sections. Crude, but it'll work.

    275:

    Why not carbonise the algae instead? (By partial burning to something like charcoal).

    276:

    Because ribs roasted on wood fire taste excellent and I very much doubt algae would be a suitable replacement.

    (We already mentioned goats in space, so from there to a goat rib barbecue there isn't much of a distance)

    277:

    Oddly enough, I prefer CO2 scrubbers for managing short term fluctuations in CO2, especially if they are regenerative. Something as simple as activated charcoal might work in some circumstances.

    The issues with using plants include:
    1. They use oxygen too. CO2 buildup often means you've got too much biomass respiring, not enough photosynthesizing. Adding biomass may not be the answer here.
    2. Plants can be slow. Yes, algae can grow fast (doubling time in days), but the difference is that CO2 scrubbers start working when you switch them on them, while algae works once you've got all the nutrient solutions and light correct. Also, algae cultures can get contaminated easily, and your best CO2 absorbing species may not be the most competitive. Keeping your cultures clean is just another one of those challenges.
    3. As you noted, getting the carbon back out of plants gets interesting. Yes, you can burn biomass, but flames in a space colony (at presumed low-G) require better management than they do on Earth.

    For middle and long term carbon and oxygen management, plants are great, and that's what I'd use them for.

    278:

    On Earth, the cycle's so huge that even big farms don't really perturb the local carbon cycle (nitrogen and phosphorus yes, carbon and oxygen, no). In a small biosphere, any crop is going to appreciably change elemental balances.

    However, a space colony has a huge advantage no terrestrial closed-cycle biosphere has got: a free cold trap! Run your atmosphere through a heat exchanger on the shadowed exterior of the colony and you can condense out CO2 while returning the N2/O2 mix to circulation (via a countercurrent exchanger to warm it back up, of course). This means you can stockpile CO2 as dry ice and use it to mechanically buffer your atmospheric pCO2. Done right, this should allow you to simulate a much larger atmosphere (for CO2 cycling purposes) than your colony can actually contain.

    It's a mechanical kludge and therefore inelegant (it's not homeostatic -- at least, not without some refinement) but it means issues like the Biosphere 2 CO2 craziness can be finessed without any monstrously high-tech extras.

    279:

    That might work too. So heat exchangers on one side of your colony for the power plant, one side shaded from the to use in refrigeration? It appears that you're setting up a nice design for your whatever-you-want-to-call-it.

    280:

    So, 279 comments in, and we've sorted out the CO2 balance ... this is going to be tricky, isn't it?

    281:

    Yup. About 16 more elements to go, not counting whatever needs to be recycled to keep the tech side running.

    282:

    Okay, to answer the question, I don't know how many species it requires to make bear. Since there's soil the in loop, no-one has ever known. I think we're trying to be too precise, like trying to work out the orbit of the moon using integral calculus on spheres before we have a theory of gravity. Perhaps we really do need that in order to make it work, in which case, we'd need to be able to create stable soil by composting, and make sure that none of the species of bacteria important to the cycle go extinct due to any circumstantial changes we make. In zero g, the movement of moisture is primarily by capillary effect, which needs a different type of soil. Perhaps it would actually make sense to run the composting in zero g, and then run the farming elsewhere.

    283:

    Using aeroponics (like hydroponics, but with saturated air underneath and a nutrient spray), the minimum number of species is two: a grain and a yeast (hops a potential third), with everything else handled through either human action or mechanical solutions.

    As noted above, the minimum number probably isn't the most efficient (in terms of calories in to calories out), nor the most resilient to system glitches. It is, however, the simplest.

    284:

    I think I've made the point before that the person we really need here is a professional cannabis farmer. They're closer than anybody else to doing serious vertical/urban agriculture in controlled environments, and they do advanced aeroponics, and they do it as a business rather than a hangar-queen research project.

    Grow-ops, microbrewing, and of course aerospace engineering. It's basically the Pacific Northwest isn't it? Begs the question "what will we do for caffeine?" though.

    285:

    I’d picked Scotland deliberately because of the crinkliness. I should have been more explicit about my desire for inefficiency. Mainly because of some of the agricultural, psychological and sociological issues implied by “Kowloon, plus high intensity agriculture”.

    High intensity agriculture would worry me. On a generation ship I’d be worried about any system that required both high quality human intervention and complex machinery to be working well all the time.
    I’m also concerned about what happens to the waste. The amount of food (and other stuff) you can take out of the system is affected by both the inputs you inject and the waste outputs you can handle. The most efficient and robust way to handle waste might be to allow more natural process to work in their own time. I think a more industrial eco-system approach would serve the ship-state and its citizen crew better. A crinkly ship-state gives you plenty of volume and therefore time to deal with compost and waste gases and dirty water. It also gives you plenty of volume in which to store stuff in case you ever need it.

    It also allows you use the same piece of real estate for multiple purposes and enrich your agriculture base. The soil is a growing medium and a sink for CO2 and home for genetically diverse microbes and a place for children to get muddy.
    Again, as you point out you can use human intervention and use the cold sink outside to render everything back to basic chemicals
    From a process efficiency point of view we might find that making each component of the system as efficient or intensive as possible makes the overall system less efficient. I’m thinking of the difference between small pipes and big pumps and big pipes and small pumps.

    We’ve been doing hydroponics and chemical fertilizers for a far shorter time than we’ve been doing farming and I’m inclined to trust the technology that has a track record of thousands of years over technology with a shorter track record when I’m picking my technology for a project lasting, well, forever.
    I think large parts of the agriculture have to be low intensity because of potential issue of scale and the avoidance of mono-cultures. If you want something once you have to look after it forever. Taking bananas as an example. If you want to take bananas with you then you could just take your favorite Cavendish variety but I would worry that this would not give you sufficient genetic diversity in your banana population to ensure robustness to a) ship-state evolved diseases b) exogenous shocks caused by e.g. the machinery breaking or political dispute c) changes in the tastes of the population. So, we may choose to take ten varieties of banana. In which case we need to keep a viable population of ten varieties of banana on the go, forever. That requires some crinkliness.

    With the ten meter high ceilings I’m using as my base case you obviously can’t do anything that requires a height much above eight or nine meters. So no rugby, limited theatre, no oak trees (no oak aged whisky), no eagles, no castelliars, no high diving, no kite flying. Any activity or output which requires a height of more than ten meters that a significant minority of your population is ever going to get vocal about you have to accommodate and that means potentially some ratio of volume to area that is not perfect.

    I’m not convinced that living somewhere with the population density of Kowloon is sustainable for everyone. Over the “mission life” of a journey to a nearby star of thousands of years you might expect between 50 and 150m to live and die in the ship-state. It’s one thing to ask someone to live in Kowloon for most of their life. It’s another to ask them, their children and their grandchildren to live like that, forever, with no hope of a change in situation and nowhere to go on their summer holiday, ever. Forever, everyone would have to live so that they can never be on the only visible person in a space and be unable to touch the walls at the same time. That way madness lies and that seems to me to be a pyschological stretch on a par with some of the science and technology that might work or might not that has cropped up on these conversations.

    Without the equivalent of the Highlands of Scotland where will dwell our poets, madmen and lighthouse keepers?

    286:

    I am fascinated by this discussion, because I am currently writing a Science Fact (not Science Fiction) book about interstellar travel. In my (as yet sketchy) plans I was presuming that on the vessel things would be done the old-fashoned way. Think, for example, of 120,000 people, split into three or four small towns, and surrounded by cultivatable soil. They would need wheat and barley (and beer), and honey - and hence bees - and cows and pigs and chickens and ducks and ... (insert very long list here). Because in any traditional village community in a prosperous country there always was (and still is) a wide variety of comestibles.
    And all - and I do mean *all* - the waste is recycled.
    In the organisation I am envisaging there is a single vessel of, say, 100 km length and 80 km width. Clearly we can't build one of these - but there are a lot of suitable asteroids out there. Hollowing out the centre (and leaving really thick walls - say 10km thick - gives us the material for firing out (ejection mass), in order that the vessel can move, and also gives us a large central chamber. We could, perhaps have several "floors" (main levels) - with very high ceilings - say 200m each, and each region of the vessel and/or each floor could be adjusted to a different climate pattern.
    And we have to have lots of variety. Not just one sort of grain, but dozens; not just one sort of beer, but many; not just one sort of wine, but white and red and whisky and sake and vodka.
    Since the vessel is rotating and has an approximate 1 g gravitational field around the central rim (we could limit our habitual use to those areas having between 0.8 g and 1.2 g), there is no problem with the bees (or wasps or hornets) trying to deal with low-gravity flight. And they will *not* be a nuisance for the machinery - as I type this, in a room with several computers, there is a beehive only three doors away: the bees are not interested in the machines, nor do they (often) come indoors.
    But the beer, as a measure of productive leeway, is a great idea - I shall have to write that in! (if I may, please?)

    287:

    I don't think the beer test is as stringent a test as it at first appears. You could presumably genetically engineer a single yeast cell to produce all of the components of beer from sugar water, and you can produce sugar water by various non-biological processes from carbon and water, given enough energy. (There's a possibility that some of the enzymes needed to produce the flavor of, say, hops, might not operate in the yeast's high-alcohol regime, in which case you might need two species, a yeast and, say, a bacterium.)

    That doesn't negate the other issues of sustainability explored in this comment thread.

    288:

    An absolute minimum is compliance with the Reinheitsgebot

    Your solution wouldn't satisfy that condition.

    289:

    No, but you wouldn't be able to tell the difference.

    290:

    I could also open up your brain and directly stimulate the relevant nerve centres. But that too would be sidestepping the point of the question, which was how create an ecology.

    (I am assuming that the same magic level of science that allows us to produce a single yeast able to produce all the interesting flavour chemicals in a Munchen brew would also allow us to do the direct neurostimulation required.)

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