Two of Everything, and a Quarantine

Everybody calls it Noah’s Ark eventually. I do too. You are building a sealed world and filling it with living things, and there is no older story than that.

But read the story again and notice what is missing. Noah took two of everything and he did not screen a single one. No quarantine, no testing, no manifest, no thought about what was living in the gut of the animal walking up the ramp. And it did not matter, because the voyage was forty days and then everybody got off.

Ours does not end. Nobody gets off. That one difference turns a parable into an engineering problem, and it is the hardest one in this magazine.

Everybody pays rent

The test I keep coming back to is rent. Every passenger has to pay it in more than one loop. If an animal only makes meat, it is cargo. If it makes meat, and eats something nothing else will eat, and returns something the soil wants, it has earned a berth. That is the whole test, and most of the animals people put on the list without thinking fail it.

So let’s walk them up the ramp one at a time and argue each one down.

Chickens

Chickens go up first, and they nearly fail on the second question.

The numbers are good. A chicken turns about 3.3 kilograms of feed into a kilogram of meat, where a pig needs 5.6, and if you keep them for eggs instead of meat the farming area drops again.¹ They want around 20 to 22 percent protein in the feed, which is less than fish demand and more than a rabbit needs.² The eggs matter more than the meat does, and I will come back to why.

Here is the problem. Chickens eat worms. The worms are the soil engine. In a sealed habitat the worm bed is not a bait bucket, it is the machine that turns everything nobody ate back into dirt, and a hen will hunt it to the last one if you let her near it. So the chicken and the worm cannot share a floor. That is not a fence problem, it is a layout problem, and it belongs on the drawings before anybody buys a bird.

The other problem is the manure. In a closed loop you have to collect what comes out, all of it, because it is the nitrogen and the phosphorus for next season. A bird scatters it across bedding and floor and you go and get it with a shovel. It can be done. It is a chore that never ends, and chores that never end are the ones that get skipped in year six.

Rabbits

Rabbits look like the right animal on paper. They want only about 16 percent protein in their feed, the lowest of the lot.² They breed fast. They eat greens nothing else wants. They are quiet, they are small, and they do not need a pasture.

And they will kill you.

Rabbit meat runs about 82 percent protein and almost no fat. A commercial rabbit carries maybe fifty to a hundred grams of fat you can cut off a two-kilogram animal, and lean wild game can come in under 3 percent.³ Eat nothing but that and you get protein poisoning, which the old northern crews called rabbit starvation, or mal de caribou. Vilhjalmur Stefansson lived eighteen months on a fatty Inuit diet in fine shape and then nearly died when the fat came out of it. It starts with diarrhea and a headache, moves to an uncontrollable craving for fat, and ends in a total loss of energy.⁴ You can eat until your belly is full and starve doing it.

So the rabbit is not a food animal by itself. It is a food animal next to a fat source, and that is what the eggs were for, and what the goat is for.

Goats

I think we carry goats, and I want to say up front that this is a live question and not a settled one.

The case for them is fat. A goat gives milk, and milk is the fat the rabbit cannot give you and the fat the greenhouse cannot grow in quantity. A goat also eats rough forage, the stalks and the trimmings and the woody stuff a rabbit will not touch, so it closes a loop nobody else closes. And when it is old, you eat it. That is three rents paid.

The case against is everything a large animal costs. Space, water, air, and a manure problem worse than the chickens because it is bigger. The published work on this is blunt: farmed animal protein in a habitat does not seem feasible today, because the area livestock take competes directly with the area people take.⁵ Biosphere 2 carried four pygmy goats and a billy from the Nigerian plateau, along with 35 hens, three roosters, and pigs, and the crew still lost an average of 16 percent of their body weight in the first mission.⁶ The goats were not the reason. But they were not the cure either.

So do we keep them, or eat them, or leave them on the ground? I do not know. I know the fat problem is real and the goat is the only animal on this list that solves it and eats what nobody else will. That gets it a hearing.

The ones that run

Deer and elk come up every time somebody sketches a big habitat, because a mile-wide barrel with a meadow in it looks like it ought to have something grazing on it. I would like that too.

But a deer is a running animal, and in a barrel there is nowhere to run. And before you even get to that, you have to get it there. I have spent a career shipping things to places that do not want them. I do not know how you button up an elk for a trip like that. Every part of its world changes at once in transit: the enclosure, the motion, the noise, the light, the smells, the handling, the temperature, and what the transport people carefully call unusual gravitational forces.⁷ That is written about a truck. Multiply it by a launch.

You can tranquilize a big animal for a day. You cannot tranquilize it for a month, and you cannot explain to it what is happening. And the animal that survives the trip arrives with whatever was living in it when it left, which brings me to the part of the Ark story Noah got to skip.

Is there another way in?

Here is a question I do not have the answer to, and I am putting it on the punch list so somebody who does can write to us.

What if you do not ship the animal at all? What if you ship the embryo? Frozen, it weighs nothing, needs no feed, no water, no air, no handling, and does not care how long the trip takes. And it is about the cleanest thing you could carry. You can wash it, test it, and screen the donor line, which is a great deal easier than certifying a live goat free of every pathogen on Earth.

Some of this has been done. Frozen two-cell mouse embryos were launched to the International Space Station, thawed there, and cultured for four days in microgravity, and they developed into blastocysts with no DNA damage anybody could detect.⁸ Freeze-dried mouse sperm sat on the station for nine months and came home to produce healthy offspring; the DNA took slight damage and the egg repaired it.⁹ So the freezing and the shipping are demonstrated.

But four days was the limit, because at that point a blastocyst has to implant in a mother or it dies. Nobody has carried a mammal to term off Earth. At the far end of the process there is a machine: an extrauterine system, essentially an artificial womb, that has carried premature lambs for up to four weeks with normal lung and brain development.¹⁰ But look at what it does. It finishes a fetus that is already most of the way there. Nobody has taken an embryo from blastocyst to a live birth in a machine, in any species. The middle stretch is empty.

So the honest picture is this: both ends exist and the middle does not. You either send a mother, live, with everything that implies, or somebody builds the middle. Is that the only way to make this happen? Are there other options I have not thought of? If you know one, write to us. That is PL-18.

And note the catch I keep tripping on. A freezer full of embryos is a vault, not a herd. A vault does not adapt. Whatever the habitat does to an animal over a hundred years, the frozen stock will not have done it, and I have already said in these pages what I think of a food supply that cannot reproduce itself.

The fish argument, and my answer

I should give the other side its due, because it is a good argument and it is the one the literature makes.

Fish beat everything on this list on the numbers. They need five to twenty times less energy than a mammal to put on a kilogram, about three times less oxygen, and they give off less carbon dioxide. And their waste is the easy kind: it stays in the water, dissolved or in particles, where a pump and a filter can pull it out, instead of being scattered across a floor.⁵ Insects are better still on feed conversion, and the Chinese ran mealworms on vegetable waste for a year inside a sealed habitat to prove it.¹¹ If you were designing purely for efficiency you would carry fish and bugs and nothing with fur or feathers, and you would be right.

I am carrying fish. I said so in Fish, Salt, or Dirt, and nothing here changes it. But a habitat that holds people for a hundred years is not only an efficiency problem. It is a place people have to want to stay, and it needs a fat source, and it needs something to eat the stalks, and it needs a margin for the year the fish tank crashes. The goat is the margin. The chicken is the fat. Efficiency picks the fish; the hundred years picks the rest.

Stowaways

Now the part Noah skipped.

Biosphere 2 imported four species of cockroach on purpose, to break down leaf litter. Then the household cockroach got in on its own and exploded to numbers that threatened the crops, and so did ants, lots of them, longhorn crazy ants, which nobody invited.¹² One account of the first mission describes the result as a post-apocalyptic veneer on the intended Ark.¹³

That is the lesson. It was not the animals they chose that got them. It was the ones that came along. Every crate, every root ball, every bale of bedding, every animal’s gut is a ship inside the ship, and you did not write the manifest for any of them. The one line in the literature I agree with completely says the animals you select for a habitat should have been raised in a pathogen-free environment on Earth and tested thoroughly before they go.¹⁴ Good. Now show me the supply chain that does that for a goat. It does not exist. It is PL-15, and it is a bigger job than the goat.

What has to be tested

I have argued four animals up the ramp and I am not sure about two of them. That is the right place to be, because nobody has run this test and I am not going to pretend the answer is in a book.

What has to happen is what always has to happen before an owner signs for a job. Somebody builds it small and breaks it on purpose. A sealed room with a worm bed and a hen and a wall between them, to see if the wall holds. A rabbit line and a goat and a real fat budget, to see if the numbers I have quoted survive contact with a kitchen. A clean-stock program for one species, start to finish, to find out what it actually costs to certify a living thing. And the middle stretch of the embryo problem, if anybody is working on it, because it is the only road that gets a large animal into a barrel without a trip that might kill it.

Until then this is a manifest with question marks on it. Noah did not need one. We do.

Ideas in Star Bound are published open — take them, build them better. Our open proposal.

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A note on where this comes from. I am not a metallurgist, a spacecraft engineer, or a degreed engineer of any kind. But I am a practical one, with more than forty years in heavy industrial construction: welding, millwright work, hydraulics, mining, and thirty-three years of electrical construction and commissioning on the North Slope of Alaska, in a place that punishes anything built wrong. Much of that time I have worked as a field engineer, which means I am the one standing in front of the equipment when the drawing turns out to be wrong, and the fix has to be made on the spot, with what is on hand, and has to work the first time. Anyone who has done that long enough learns that a lot of engineering gets corrected in the field by people with more experience than the people who drew it. That is the eye I bring to these subjects: not what should work on paper, but what actually gets built, and what breaks. The facts I take from other people are footnoted so you can check them and read further. The ideas built on top of those facts are my own, and I would rather see them knocked down by somebody who knows better than left standing because nobody looked.

Sources

1. Cortes A. J. et al. (2021). “Supplementing Closed Ecological Life Support Systems with In-Situ Resources on the Moon.” Frontiers / PMC — feed conversion of about 5.6 kg feed per kg pork and 3.3 kg per kg chicken; keeping chickens for eggs alone reduces farming area — https://pmc.ncbi.nlm.nih.gov/articles/PMC8401783/ ↩
2. “Bootstrapping Space: Life Support — Animals for food” (2015) — protein requirements in feed: fish about 36 percent, chickens 20–22 percent, rabbits about 16 percent — https://phobosorbust.blogspot.com/2015/08/life-support-animals-for-food.html ↩
3. Optimising Nutrition, “Rabbit Starvation” — rabbit meat about 82 percent protein; commercial rabbit yields roughly 50–100 g dissectable fat per 2 kg live weight; lean game sometimes under 3 percent fat — https://optimisingnutrition.com/rabbit-starvation/ ↩
4. Hektoen International, “Rabbit starvation: protein poisoning” (2022) — Stefansson’s eighteen months on an Inuit diet and near-death on lean meat; symptoms of diarrhea, headache, fat craving, and loss of energy — https://hekint.org/2022/01/26/rabbit-starvation-protein-poisoning/ ↩
5. Przybyla C. (2021). “Space Aquaculture: Prospects for Raising Aquatic Vertebrates in a Bioregenerative Life-Support System on a Lunar Base.” Frontiers in Astronomy and Space Sciences — farmed land-animal protein in a habitat judged not feasible today; fish need 5–20× less energy and about 3× less oxygen than mammals; fish waste stays in the water where it is easily removed — https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2021.699097/full ↩
6. Environment & Ecology, “Biosphere 2” — first-mission livestock: four pygmy goats and one billy goat from the Nigerian plateau, 35 hens and three roosters, pigs; crew lost an average of 16 percent of body weight — http://environment-ecology.com/ecological-design/255-biosphere-2.html ↩
7. National Research Council (2006). Guidelines for the Humane Transportation of Research Animals, “Good Practices in the Transportation of Research Animals” — during transport nearly every aspect of an animal’s environment changes at once, including unusual gravitational forces — https://www.ncbi.nlm.nih.gov/books/NBK19639/ ↩
8. Wakayama S. et al. (2023). “Effect of microgravity on mammalian embryo development evaluated at the International Space Station.” iScience / PMC — frozen two-cell mouse embryos thawed and cultured aboard the ISS for four days, developing to blastocyst with no detected DNA damage — https://pmc.ncbi.nlm.nih.gov/articles/PMC10725056/ ↩
9. Wakayama S. et al. (2017). “Healthy offspring from freeze-dried mouse spermatozoa held on the International Space Station for 9 months.” PNAS — slight DNA damage in space, repaired by the oocyte; normal birth rate and offspring — https://www.pnas.org/doi/10.1073/pnas.1701425114 ↩
10. Partridge E. A. et al. (2017). “An extra-uterine system to physiologically support the extreme premature lamb.” Nature Communications 8, 15112 — eight fetal lambs supported for up to four weeks from about 105–120 days gestation, with normal lung and brain development — https://www.nature.com/articles/ncomms15112 ↩
11. “Insects in bioregenerative life support systems: unlocking their role in space sustainability” (2025). PMC — silkworm, mealworm, and black soldier fly as the studied candidates; mealworms raised on vegetative waste during the Lunar Palace 1 sealed closures — https://pmc.ncbi.nlm.nih.gov/articles/PMC12457449/ ↩
12. Dartmouth Alumni Magazine, “Biosphere 2: What Really Happened?” — four beneficial cockroach species imported; household cockroaches and stowaway ants exploded to crop-threatening numbers — https://dartmouthalumnimagazine.com/articles/biosphere-2-what-really-happened ↩
13. Baltimore Sun guest commentary (Oct. 2023), “Biosphere 2: What a 30-year-old experiment taught us about living on Mars” — longhorn crazy ants and the post-apocalyptic veneer on the intended Ark — https://www.baltimoresun.com/opinion/op-ed/bs-ed-op-biosphere-2-anniversary-20231009-f2bxy2hrffhdbgv2r5uz44nh3i-story.html ↩
14. NASA SP-428 / Space Resources Vol. 4, “Life Support and Self-Sufficiency in Space Communities” (via National Space Society) — animals selected for a space habitat should be raised in a pathogen-free environment on Earth and tested thoroughly — https://nss.org/settlement/nasa/spaceresvol4/lifesupport.html ↩