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I'm not convinced Mars can support a large human population even with initial massive economic subsidy. Pregnancy in the high radiation and low gravity of Mars

by codex 13y ago

I'm not convinced Mars can support a large human population even with initial massive economic subsidy. Pregnancy in the high radiation and low gravity of Mars may result in low fertility rates and some very... interesting, (misshapen, if not defective) new humans. Unfortunately the only studies, which were kind of bad, were conducted in zero G and not 0.4 G [1], and the embryos were quickly transferred into mice in 1G for neonatal development and birth. Even if fetal development in microgravity is OK, absent DNA repair technologies, radiation induced decay of the gene pool over the generations may require a continual replenishment of fresh, "unmutated" DNA from Earth--at least until humans evolve sufficiently on Mars. It is not practical to assume no additional radiation exposure on Mars: even if humans are buried underground, and do not come out during the occasional solar storm, they must occasionally walk on the Martian surface. Otherwise it's a robot's world, and human colonization is merely an exercise in preserving the human race though Martian burial in case of Earth apocalypse. [1] http://www.everythingology.com/mammalian-reproduction-in-space http://www.everythingology.com/mammalian-reproduction-in-spa...: "These results suggest for the first time that fertilization can occur normally under G environment in a mammal, but normal preimplantation embryo development might require 1G"

stcredzero 13y ago
> radiation induced decay of the gene pool over the generations Exercise: think of inexpensive ways of mitigating this. Took me about 2 seconds to think of 3. Low gravity might be an issue. Given the record on biological processes we thought earth-normal gravity would be vital for, I doubt it, however. I did find one mention of lower fertility rates from microgravity. http://www.wired.com/wiredscience/2009/08/spacebabies/ http://www.wired.com/wiredscience/2009/08/spacebabies/ But if all microgravity does is to lower fertility, even that's not a problem. 38% of earth's gravity probably won't be a showstopper.
- chii 13y ago
  > Exercise: think of inexpensive ways of mitigating this. Took me about 2 seconds to think of 3. instead of "leaving it as an exercise to the reader", why don't you list your three cheap ways to mitigate gene pool decay? coz i can't see any cheap ways - anything coming from earth will cost an arm and a leg.
  - cbhl 13y ago
    For example, if the fertility rate is lower (but not zero), you can try a "quantity, not quality" approach. My parents had like a half dozen siblings each; nowadays people only have one or two kids but they could easily try for more within a lifetime.
  - stcredzero 13y ago
    > coz i can't see any cheap ways - anything coming from earth will cost an arm and a leg. Good point: Relatively inexpensive. 1) Zygotes, sperm and eggs are very small. Even with radiation shielding, it's not that expensive to ship a whole lot of them from Earth. These can be used to "refresh" genetic information from Earth and ensure enough genetic diversity. If medical technology has progressed far enough, it may even be possible to send sequencing data and avoid shipping material altogether. 2) Keep everyone born on Mars underground and shielded from radiation, at least until they can store their genetic material in radiation immune facilities for breeding later. 3) Everyone immigrating from Earth would be wise to store and ship their own genetic information. This can be sent on the same flights with the "backup diversity" information in (1), which would greatly minimize the cost. The marginal cost for another sample of eggs/sperm is going to be pretty low. Also keep in mind that not every launch has to contain such information.

by codex 13y ago

stcredzero 13y ago

> radiation induced decay of the gene pool over the generations Exercise: think of inexpensive ways of mitigating this. Took me about 2 seconds to think of 3. Low gravity might be an issue. Given the record on biological processes we thought earth-normal gravity would be vital for, I doubt it, however. I did find one mention of lower fertility rates from microgravity. http://www.wired.com/wiredscience/2009/08/spacebabies/ http://www.wired.com/wiredscience/2009/08/spacebabies/ But if all microgravity does is to lower fertility, even that's not a problem. 38% of earth's gravity probably won't be a showstopper.

chii 13y ago
> Exercise: think of inexpensive ways of mitigating this. Took me about 2 seconds to think of 3. instead of "leaving it as an exercise to the reader", why don't you list your three cheap ways to mitigate gene pool decay? coz i can't see any cheap ways - anything coming from earth will cost an arm and a leg.
- cbhl 13y ago
  For example, if the fertility rate is lower (but not zero), you can try a "quantity, not quality" approach. My parents had like a half dozen siblings each; nowadays people only have one or two kids but they could easily try for more within a lifetime.
- stcredzero 13y ago
  > coz i can't see any cheap ways - anything coming from earth will cost an arm and a leg. Good point: Relatively inexpensive. 1) Zygotes, sperm and eggs are very small. Even with radiation shielding, it's not that expensive to ship a whole lot of them from Earth. These can be used to "refresh" genetic information from Earth and ensure enough genetic diversity. If medical technology has progressed far enough, it may even be possible to send sequencing data and avoid shipping material altogether. 2) Keep everyone born on Mars underground and shielded from radiation, at least until they can store their genetic material in radiation immune facilities for breeding later. 3) Everyone immigrating from Earth would be wise to store and ship their own genetic information. This can be sent on the same flights with the "backup diversity" information in (1), which would greatly minimize the cost. The marginal cost for another sample of eggs/sperm is going to be pretty low. Also keep in mind that not every launch has to contain such information.