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I'd like to have a community of humans live indefinitely in space habitats (think space stations supporting mining operations in the asteroid belt).

The technology would be "day after tomorrow"-level; no anti-gravity, no effector fields, or the like.

So, my problem is that I'd like to have happy space families, but I've read that long-term zero-G living is dangerous and bad for many physical systems, especially bones. The big question is whether a child can successfully be brought to term in zero gravity.

Will the children be able to be born? As a possible mitigation, we could spin the habitats, but I'm not sure if that will be "good enough" to substitute for gravity, nor whether current construction methods will be able to hold up under relentless spinning.

Please help, the gallant colonists of Alpha Colony need answers!

akaioi
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    Food for thought: will they prefer natural delivery or C section? – user6760 Nov 06 '17 at 04:27
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    we could spin the habitats, but I'm not sure if that will be "good enough" to substitute for gravity - there is no physical difference between living under 1g gravity and living in a spinning ship which replicates 1g gravity. In other words there is nothing special about gravity as a force. – bon Nov 06 '17 at 10:19
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    Technically there is a difference, but it's not important for everyday life. – Fabian Röling Nov 06 '17 at 10:21
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    You may be overestimating the issues of a spinning habitat. It wouldn't be trivial because we've yet to build a structure like that and thus have no experience, but there's nothing particularly crazy about it nor are there any outlandish structural stresses. Consider that the simplest form is just two modules attached to the ends of a tether and spun up. – Elukka Nov 06 '17 at 11:58
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    The reason we haven't built a spinning habitat is because we're not up to the point of having a sufficiently large habitat in space. The technology (and scientific knowledge) to make such a habitat spin is already available and no real obstacle. Also, "be able to hold up under relentless spinning" is not a problem: once the rotation has been set in motion, it mostly doesn't need to be powered anymore (conservation of angular momentum). Any interference by people moving around should cancel itself out, and friction losses will be negligible. – Flater Nov 06 '17 at 12:29
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    Just to finish my thought, we will need to maintain the rotation speed for very minor losses (friction losses, collision between the habitat and other object, ...) but these are relatively small energy losses and adding the lost energy won't really put any stress on the system (since we're talking about small doses of energy needed). Realistically, there's no real issue caused by long-term rotation. – Flater Nov 06 '17 at 12:31
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    https://www.youtube.com/watch?v=jTL_sJycQAA Maybe to throw in something from vsauce. Have seen this video some time ago, don't know how relevant/helpful this is. I can't remember much from it, just searched it really quick at work.. – Top Questions Nov 06 '17 at 13:10
  • Wouldn't you get dizzy because of the rotation? Pressumably it would rotate much faster than the earth does... – johk95 Nov 06 '17 at 14:10
  • If you're in the asteroid belt, you can use a small asteroid as the counterweight, with a habitat connected by a long cable. If the asteroid has much more mass than the habitat, it doesn't need to hold up under 1g. – JollyJoker Nov 06 '17 at 14:29
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    @johk95 As long as you don't look out of the window, you literally can't tell. Oh, and the moment you start moving around, or if you trow a ball (you can leap and throw a ball further in the direction against the rotation), you notice it. But it doesn't affect your inner ear and sense of balance to make you motion sick the way you do when you turn around on the spot. – Arthur Nov 06 '17 at 14:40
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    The Expanse Series of novels (read the originals, not the SciFi televised versions) takes a reasonably believable look at your question. They include the coriolis effect when you get too near the center of a spinning structure, which means if you turn your head there, you get dizzy really quickly. For this reason, most wheel designs are enormous - close to a mile in diameter. https://en.wikipedia.org/wiki/Rotating_wheel_space_station – GlenPeterson Nov 06 '17 at 14:52
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    “Day after tomorrow.” Alright guys, we have two days to build those anti-gravity and effector fields. No pressure. – DonielF Nov 06 '17 at 16:13
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    @DonielF not "no pressure" guys, "no gravity"! See, this is why the project is behind schedule... – akaioi Nov 06 '17 at 16:28
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    @bon haven't you noticed? This gravity is all coppery around the edges, it's not real... ;) – Restioson Nov 06 '17 at 17:15
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    @Arthur You wouldnt notice it by moving with or against the rotation, as the air inside would also be spinning. There may eventually be some frictional lag, but this would be on the order of the minor corrections noted by Flater and would be negligible – Redja Nov 06 '17 at 20:01
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    @Redja If you move with or against the rotation, you change your rotational speed, and thus the centripetal force of the four acting to keep you in rotation and the equal and opposing force, which is you apparent weight. If you are capable of running at the rotational speed, and do so against the rotation, you will be weightless. – Arthur Nov 06 '17 at 20:39
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    Well, if you don't want to spin the habitat, you could always use the apparatus for facilitating the birth of a child by centrifugal force. (Note: Please don't do this. It's a terrible idea.) – Arcanist Lupus Nov 07 '17 at 05:48
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    Early on, embryo has discrete spherical symmetry. Differentiating into organs requires breaking the symmetry. On Earth, one of the symmetry-breaking effects is gravity. If differentiation of cell groups requires external symmetry breaking as opposed to spontaneous symmetry breaking, then proper gestation in zero g environment might be impossible. – M i ech Nov 08 '17 at 01:26
  • @Miech No it would't because living in a spinning 1g habitat is the same as living under 1g gravity. There's nothing special about gravity. – bon Nov 17 '17 at 18:54

5 Answers5

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Last time I looked into this I was amazed these experiments (mammalian conception to delivery in orbit) had not been done. I figured I just had not found it and so I dug in this time. For mammals, they have not been done. Pregnant rats have gone to space and come home and delivered so microgravity is not immediately lethal to a fetus. Rats mated in space (no pregnancies). Rat pups nursed in space (it is tricky for them to orient; I think humans will have less trouble with that). The news from 2017: freeze dried mouse sperm (I did not know that was possible - the freeze drying) can come home and make babies. From that article.

Sayaka Wakayamaa et al, Healthy offspring from freeze-dried mouse spermatozoa held on the International Space Station for 9 months. PNAS 114(23)5988–5993

So far, the effects of microgravity on early development have been studied using sea urchins, fish, amphibians, and birds. These studies have concluded that microgravity does not prevent animal reproduction. However, because of the difficulty in maintaining mammals and performing experiments in space, studies of mammal reproduction in space have not progressed as well as in other animals, and only a few papers have been published. Those studies and our previous study have suggested that mammalian reproduction in space under conditions of microgravity cannot be easily compared with reproduction in other species.

It is lame to answer a question with "no-one knows" but for the prospects of full on start to finish mammalian pregnancy and gestation in space I think no-one knows. It is a surprise to me that is still the case.

Willk
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    +1 for a no one knows answer. Sometimes pointing out the boundaries of what is known is enough to justify the funds to get research done. – steverino Nov 06 '17 at 04:09
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    note the study was focused on the effects of radiation on fertilization not microgravity and development. Studies focusing on the gravity do not show promising results, the pre-implantation stage of embryo development is believed to be the most vulnerable. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0006753 of course microgravity plays havoc on adults too (like making them go blind) it just takes longer, so simulating gravity will be important no matter what. – John Nov 06 '17 at 05:33
  • A link explaining what is known about Space Blindness as mentioned in the comment by @John for the curious. – StephenG - Help Ukraine Nov 06 '17 at 07:22
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    +1 for letting me know astronauts in space are milking male rats and freeze dry the results. Tax money well spent – Raditz_35 Nov 06 '17 at 08:50
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    @Raditz_35: ...for the purpose of researching the effect of higher radiation on the sperm DNA. Yes, that is tax money well spent, and it's not as if it were a major cost factor. Better than many wasteful projects conducted here on earth. Are you sure you aren't just put off by the perceived grossness of "milking" rats? – DevSolar Nov 06 '17 at 09:38
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    @DevSolar I think you almost get my comment – Raditz_35 Nov 06 '17 at 10:16
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    "Rats mated in space (no pregnancies)". If that turned out to be due to lack of gravity messing with sperm travel (or any other space reason), you could make a good story or plot point out of couples deciding to have a child needing to return to the planet. It's a cool way of adding artificial natal philopatry to humankind, and what that could mean by way of control by a government/family body or wrapping the act into some sort of religious event. – Philbo Nov 06 '17 at 10:40
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    @Philbo Centrifuges are going to be much cheaper than landing and taking off from a planet unless we have near-beanstalk level tech. And if we have near-beanstalk level tech, we can pull off enough mass for rotating habitats. On the other hand, leaving non-rotating station/craft/house and going to a rotating station to have kids makes sense. – Yakk Nov 06 '17 at 15:56
  • Intuitively, one might think yes and no for this. Yes, because babies are grown floating about in fluid, and so microgravity might actually make that a little easier for them. No, because the mother walking about, turning over, etc all has an effect on the baby, and one would think it would help baby learn to move about and turn over itself. Another "no" is that without normal gravity, would the baby know where to 'engage' in readiness to be born? – Ralph Bolton Nov 07 '17 at 15:58
  • This is a good answer, especially when combining the input from the comments like @John 's, the study referenced in that article has been published as well: http://www.nejm.org/doi/full/10.1056/NEJMoa1705129 – kcar Nov 07 '17 at 21:56
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Will the children be able to be born?

For all we know: Yes.

I shamelessly copy from two comments below the question by user6760 and bon.

For the birth gravitation is usually helpful in assisting the pushing force of the contractions. Many women stand or sit during the birth. However, it is conceivable that even without gravitation there is enough force to push the baby out of the uterus. In the same way one could also help and create artificial pull by applying a suction cup to the head of the baby and pull.

Or one could apply a C-section which would eliminate the need for gravitation at all during birth.

Rotating elements creating artificial gravitation similar to our gravitation level are feasible. During infinite space travel you don't have to do without gravitation. In the absence of friction with the surrounding space, such a rotation could be maintained very efficiently. Centrifugal forces are exactly the same as gravitational forces. Regarding the endurance of the construction towards rotation, please note that space vehicles have to endure a multiple of that force during launch and they do. An infinitely traveling human space race surely would replace weak parts over time with newer parts to hold it all together.

And even if for most of the time you would life in low-G environments, by doing sports in this environment (pushing against each other, ...) one could keep the muscles trained.

For the skeleton it may indeed by bad in the long run. We don't have reliable long term information about that. The human race living in low-G might indeed evolve different (less upright). Maybe modern medicine (the technology of today to tomorrow) could strengthen the bones artificially (increased calcium uptake,...).

NoDataDumpNoContribution
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  • Or one could apply a C-section which would eliminate the need for gravitation at all during birth - oh, but the mess... – Mathieu Guindon Nov 06 '17 at 18:07
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    "water birth" is a thing for contemporary humans on Earth, and my wife enjoyed the relief of swimming while very pregnant... low gravity is probably more comfortable for both mom and baby than normal gravity during pregnancy and birth. – Nathan Nov 06 '17 at 19:41
  • Trilarion, very interesting angle here. I wonder if the women would go into the center of the habitat (low/zero-g section) for giving birth. The exercises you're speaking of, those are "isometric exercise", yes? – akaioi Nov 07 '17 at 04:23
  • @Nathan water does not remove gravity at all. It just sustain your body. – Antzi Nov 08 '17 at 02:52
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    water birth is just interesting to compare since buoyancy is often used to simulate low gravity – Nathan Nov 10 '17 at 22:11
  • My wife gave birth to three kids on her back with no help at all from gravity. Gravity is really overrated when it comes to childbirth. – Clearer Jan 02 '18 at 23:11
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Ugh... So, yeah, it's never been done - if it had, this would be open and shut.

Birth

  1. Human women often give birth prone such that the force of gravity is perpendicular to the direction they're pushing the baby. Therefore, there's no reason to assume that [most] women aren't strong enough to give birth in zero-g.

  2. Women from a variety of species (including some humans) give birth under water where the forces of buoyancy and gravity are equal and opposite, so there's still no reason to suspect that gravity is a requirement for birth.

  3. One of the long term effects of weightlessness is that our bones become weaker. It's possible (though, highly unlikely because the baby doesn't go between hips - it goes through cartilage and other tissues) that this would mean that giving birth necessitated a risk of breaking one's hips. It's also possible that the bones could become more pliable, either because of the sometime inverse relationship between strength and plasticity, or because of a drug/supplement administered during gestation.

  4. If birth without undue risk of catastrophic injury was not possible, there's always Cesarean section, see bulldogs.

Dropping

In the weeks to hours before birth, the baby resides lower in the abdomen - a transition that physicians call "lightening". A hypothesis has been advanced that a baby won't drop without gravity. On the surface, it seems to have merit, but babies drop while expecting mothers are in a variety of positions. In addition, dolphins appear to have a similar phase, so at the very least, mammal babies can drop without gravity. Earth women have exercises and movements which hypothetically move the baby into position, but while that research appears to be in its infancy, there's no reason to avoid talking about the zero-g versions of the same exercises.

Gestation

Humans carry babies in their wombs surrounded by hydro-static pressure. Since Earth women do yoga, swim and sleep, it's pretty clear that their orientation does not effect their ability to bring a baby to term. For women to need gravity to bring babies to term would require proof.

Copulation

Again, nobody wants to admit to having had sex in space, but humans are endlessly creative when it comes to this. I will not be adding a link.

Evolution

Nature will find a way. There are few things that cause rapid evolution in "natural" species, but illnesses and breeding problems are at the top of that list. Nature is neither fair, nor kind about this, so there would be some cruel generations where natural selection takes care of this problem. That could have it's own consequences because our powerful brains are related to the long gestation times. The other option would be to guide evolution with Genetic Engineering, but that tech is probably a long way away.

Verdict

If you want it to be an issue, you can, but I wouldn't bat an eye if a fiction writer told me that zero-g birth was commonplace and about as catastrophic as Earth birth.

user121330
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    "Humans carry babies in their wombs surrounded by hydro-static pressure" that's a really good point which I hadn't considered. The issue I'm worried about is at the very end, when the baby "descends" to get into position ... might want some gravity for that. As other posters have said, C-section might be the preferred option here. Your comments have mitigated a lot (not quite all!) but a lot of my concern! – akaioi Nov 07 '17 at 20:22
  • "laying down" -> "lying down". Please. – ErikE Nov 07 '17 at 23:16
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    Babies and children need quite some "exercise" to grow up really healthy, but from our experience with individuals with certain permanent disabilites (or ones growing up in front of a TV), we know this is not fatal, and could most likely be taken care of by some daily age-adapted gynmastics also in space. – Karl Jan 02 '18 at 21:00
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Having done it myself, I know that birth is a very traumatic experience, for all persons involved. Pregnancy can also be very unpleasant.

There will be no room for people on space stations who are going to be sick and wobbly and faint for months at a time.

Your future humans will leave gestation to a nice safe, warm automatic womb, providing everything the baby colonist needs, including gravity, and when it's finished growing, you open the lid and get it out.

RedSonja
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    Nice for near future or beyond, but right now we don't have the tech to grow a baby in a machine. – JPhi1618 Nov 07 '17 at 16:22
  • @JPhi1618 I'm pretty sure we can have that kind of tech in a decade or so, if we just allow cloning humans. – Clearer Jan 02 '18 at 23:10
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    The space program has had no shortage of encounters with vomit, urine, and stray pieces of feces floating around the cabin. But there's still a risk that when the water breaks, the ship's systems will have met their match. It's also said to be possible to drown in a quite small amount of water in zero G if it gets stuck in the throat. Birth may indeed be a traumatic experience for all involved... – Mike Serfas Jun 16 '22 at 14:26
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My suspicion would be that it is possible to make babies is space, but I think there would be a far higher rate of in-utero fetal demise. Microgravity shouldn't cause any obvious issues with conception, formation of a blastocyst, or implantation (emphasis on the obvious). The placenta forms in any orientation so that shouldn't be an issue. For the first 32 weeks or so of a pregnancy baby spins and flips like a toddler in a bouncy house, so orientation doesn't seem to be particularly important. Some of the other comments suggest that gravity plays a role in fetal engagement with the cervix, descent, and birth, but at the end of the day those are mechanical problems that can be solved. We deliver babies all the time without Mom going into labor either through induction of labor or via cesarean.

Where you may get into trouble is with Vircohow's Triad, particularly the stasis corner. An astronaut recently had a blood clot form in his neck while in microgravity, possibly due to an increase in blood pooling in the head and neck in microgravity (gravity usually "pulls" the blood back to the heart from the head). The placenta has a boatload of blood vessels for nutrient exchange with baby and can cause fetal demise if a clot forms in it. It's unclear whether microgravity would increase susceptibility to blood pooling in the vessels in the placenta, but if it did that could increase the rate of fetal death.

I think the nastiest thing about growing up in microgravity would be changes in the vestibular system of your inner ear that helps you balance. A child's brain raised in microgravity would never receive the typical signals from the inner ear that you or I get while being accelerated into earth's surface. This would either lead to something like ambliopia of the ear, where the brain simply ignores the signals it gets, or re-interpretation of the signals as they operate in microgravity (more likely). The second would cause people born in space to be very disoriented at mild to moderate linear acceleration (such as spacecraft maneuvers) the same way we get disoriented on a merry go round. This same effect would happen when they go down a gravity well, though presumably they would eventually get used to it the same way astronauts get used to the vestibular changes in microgravity. Those first couple days would be nasty though.

L.Dutch
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Jim
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