[ExI] Should we still want biological space colonists?

[BillK]

On Fri, 7 Feb 2025 at 14:17, Giulio Prisco via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> Yes, but at the end I say:
>
> The logic of this seems very solid. However…
> ...
> So forget what I said, and let’s build those little crewed outposts on
> the Moon and then Mars. Our mind children will likely take over one
> day, but let’s have some useful fun before.
> _______________________________________________



It's only fun for humans on short trips, before they rush back to the
safety of the earth environment.
Apart from the basic needs of supplies of food, water, fuel, medical
treatment, etc., I asked a westernised version of DeepSeek R1 AI for a list
of the medical problems that humans encounter while away from earth. See
the impressive list below.
As Adrian says, for weak humans to leave earth long-term, they have to
build earth-like environments (including gravity) to live in.
BillK


DeepSeek R1 AI -

When humans venture beyond Earth's protective gravity and magnetic field,
they face a complex array of medical challenges from radiation and
microgravity. These risks manifest as both immediate physiological
disruptions and long-term degenerative effects, requiring careful
mitigation strategies for safe space exploration.

## Radiation Exposure Risks
- **Acute radiation sickness**: Doses exceeding 200 rad can cause nausea,
vomiting, and bone marrow damage, with >1,000 rad being fatal[1][4]
- **Cancer risk**: Galactic cosmic rays increase lifetime cancer
probability by damaging DNA and suppressing tumor-suppressing genes[2][5][9]
- **Central nervous system damage**: Linked to accelerated Alzheimer's
disease progression and cognitive decline[2][9]
- **Cataracts**: Radiation-induced lens opacity observed in 39% of
astronauts after 6-month ISS missions[2][5]
- **Immune suppression**: Lymphocyte damage increases infection
susceptibility and reduces vaccine efficacy[2][8]

## Microgravity Effects
- **Muscle atrophy**: Up to 20% loss in calf muscle mass within 11
days[8][9]
- **Bone density loss**: 1-1.5% monthly reduction (vs 1% per decade on
Earth), risking fractures and kidney stones[2][8]
- **Fluid redistribution**: Causes:
  - Puffy face syndrome and leg volume loss ("bird legs")[3]
  - Vision impairment from optic nerve swelling[2][8]
  - Balance disorders lasting years post-flight[2][3]
- **Cardiovascular deconditioning**: Includes orthostatic intolerance and
reduced aerobic capacity[2][8]

| System | Short-Term Effects | Long-Term Consequences |
|--------------|---------------------------|----------------------------------|
| Vestibular | Space motion sickness (40-50% of astronauts)[3] | Permanent
balance disorders[2] |
| Circulatory | Facial edema, nasal congestion | Atherosclerosis
acceleration[8] |
| Skeletal | Acute back pain | Osteoporosis-like fragility[2][9] |

## Additional Health Threats
- **Immune dysfunction**: Reduced T-cell activity and altered cytokine
production[6][8]
- **Microbiome disruption**: Increased virulence of pathogens like
*Salmonella*[2]
- **Psychological stress**: Includes isolation-induced anxiety and sleep
cycle disruption[2][8]
- **Telomere alterations**: Unexpected lengthening during flight with
cancer risk implications[6]

The combination of **RIDGE factors** (Radiation, Isolation, Distance,
Gravity fields, Environment) creates compounded health risks requiring
multi-system countermeasures. While modern spacecraft shielding and
optimized transit routes reduce Van Allen belt exposure to <1% of mission
radiation dose[4], deep space exploration beyond Earth's magnetosphere
remains a formidable physiological challenge demanding advances in
protective technologies.

Citations:
[1]
https://space.stackexchange.com/questions/29579/can-we-survive-van-allen-belt-radiation
[2] https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_human_body
[3]
https://www.bbc.co.uk/sn/tvradio/programmes/spaceodyssey/healtheffects.shtml
[4]
https://blogs.esa.int/orion/2022/12/10/the-van-allen-belts-are-they-dangerous/
[5]
https://www.frontiersin.org/journals/nuclear-medicine/articles/10.3389/fnume.2023.1225034/full
[6]
https://www.science.org/content/article/astronauts-face-health-risks-even-short-trips-space
[7] https://www.physoc.org/magazine-articles/the-invisible-space-killers/
[8] https://pmc.ncbi.nlm.nih.gov/articles/PMC9818606/
[9] https://www.nature.com/articles/s41526-020-00124-6
[10]
https://www.technologyreview.com/2019/10/21/132524/nasas-van-allen-probes-are-no-more-and-we-owe-them-a-lot/
[11] https://www.ncbi.nlm.nih.gov/books/NBK223785/
[12]
https://www.bbc.com/future/article/20230927-what-a-long-term-mission-in-space-does-to-the-human-body
[13] https://www.nature.com/articles/s41526-020-00124-6
[14] https://www.lpi.usra.edu/education/explore/space_health/background/
[15] https://science.nasa.gov/biological-physical/stories/van-allen-belts/
[16] https://www.nasa.gov/hrp/hazards/
[17]
https://www.science.org/content/article/astronauts-face-health-risks-even-short-trips-space
[18] https://www.nasa.gov/wp-content/uploads/2010/06/smiii_problem7.pdf
[19] https://www.nasa.gov/directorates/esdmd/hhp/space-radiation/
[20] https://news.mit.edu/2017/anthropogenic-effects-of-space-weather-0531
[21]
https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(24)00224-2/abstract
[22] https://www.nasa.gov/humans-in-space/the-human-body-in-space/
[23] https://www.ncbi.nlm.nih.gov/books/NBK222157/
[24]
https://www.technologyreview.com/2019/10/21/132524/nasas-van-allen-probes-are-no-more-and-we-owe-them-a-lot/
[25] https://pmc.ncbi.nlm.nih.gov/articles/PMC10896920/
[26]
https://www.bcm.edu/academic-centers/space-medicine/translational-research-institute/space-health-resources/how-the-body-changes-in-space
[27] https://humans-in-space.jaxa.jp/en/life/health-in-space/body-impact/
[28] https://pmc.ncbi.nlm.nih.gov/articles/PMC8550337/
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