[HN Gopher] A Primer on Long-Duration Life Support
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       A Primer on Long-Duration Life Support
        
       Author : zdw
       Score  : 54 points
       Date   : 2026-03-27 01:00 UTC (4 days ago)
        
 (HTM) web link (mceglowski.substack.com)
 (TXT) w3m dump (mceglowski.substack.com)
        
       | adolph wrote:
       | This is a great read and unironically I want to subscribe to the
       | substack, which is titled "Mars for the Rest of Us." The author
       | is that Ceglowski of Pinboard and occasional space essays at
       | idlewords.com, both of which make this self-recommending for me
       | at least.
       | 
       | It's a cliche that space exploration creates discoveries that
       | improve life back here on Earth. In the topics discussed in this
       | essay, water reclamation and waste recycling especially, the
       | future solutions developed I think will lead to improvements for
       | terrestrial living.
        
       | buildsjets wrote:
       | A note on their section on fire extinguishing - just about all
       | aerospace fire extinguishing systems use agents with a fluorine
       | based chemistry. Putting out a fire dissociates some of the
       | agent, and in the presence of humidified air it recombines and
       | forms hydroflouric acid, which will eat you from the inside out.
       | So your air scrubbers had best do a good job at removing acid
       | gasses.
       | 
       | https://www.researchgate.net/publication/280646417_Acid_gas_...
        
         | XorNot wrote:
         | It doesn't really eat you though: HF is so small that the
         | problem is it just traverses straight through the skin into
         | your blood and causes fluoridosis.
         | 
         | There's been more then a few metallurgy lab deaths because
         | someone spilled a substantial amount of HF on themselves and
         | didn't realize it.
        
       | emptybits wrote:
       | "The limiting factor in urine distillation is actually the high
       | level of calcium          from disintegrating astronaut bone, a
       | nice example of how problems in space find          ways to
       | compound one another."
       | 
       | Sobering. One of the many long term effects of life away from
       | Earth.[1]
       | 
       | With humanity's future probably (?) driving more of us to leave
       | the planet, I'm glad these things are being studied. Where
       | there's a will, there's a way.
       | 
       | [1] "Long-term space missions' effects on the human organism:
       | what we do know and what requires further research"
       | https://pmc.ncbi.nlm.nih.gov/articles/PMC10896920
        
         | imglorp wrote:
         | They mention a botched drug study but I'm curious why that
         | wasn't redone correctly given how many years we've been at
         | this. And growing plants for that matter. Hop to it guys, we
         | have to get this figured out while we have a station.
        
         | PowerElectronix wrote:
         | They need to come up with either spinning ships or suits that
         | compress you enough to activate the bones (they are
         | piezoelectric so they naturally catch calcium ions when under
         | stress).
        
       | isoprophlex wrote:
       | On water reclamation:
       | 
       | > On the Mir space station, this used to happen organically.
       | Collecting water was a grubby job that involved chasing beach-
       | ball sized spheres of condensate around the colder parts of the
       | spacecraft with trash bags before they could climb into the walls
       | and cause mayhem. Crew members spent three to four hours a day on
       | this dirty and difficult task.
       | 
       | That sounds, frankly, horrible.
       | 
       | It made me think that the average space module probably smells
       | like moist, reheated ass, too.
        
         | malfist wrote:
         | Mir famously stank. Though you'd be glad to know without
         | gravity your nose doesn't work as well
        
       | oersted wrote:
       | Curious that both average inputs and outputs match to exactly
       | 5.74 kg. I had intuitively assumed there would be a significant
       | difference, but I suppose that even if a lot of energy is
       | extracted, the mass difference will be negligible, mc2 and all.
       | 
       | I'm also surprised that the vast majority of the output carbon is
       | in the form of CO2 rather than feces.
       | 
       | It's all rather obvious in retrospect, it was just nice to see
       | crystallized like this.
        
         | birdsongs wrote:
         | > I'm also surprised that the vast majority of the output
         | carbon is in the form of CO2 rather than feces.
         | 
         | Not sure if you know, but in the same vein, I was shocked when
         | I learned ~50% of the biomass of trees is carbon (right, we
         | knew that), but _also_ that the carbon came from CO2 the tree
         | respirated. Also makes total sense in hindsight, but still
         | think it 's so cool.
         | 
         | The trees literally build their mass from the air and sunlight
         | (and yes, obviously also water and trace minerals from the
         | roots).
        
           | adolph wrote:
           | There is a nice Feynman children's lecture about this [0]
           | from the series "Fun to Imagine" [1]
           | 
           | 0. https://www.youtube.com/watch?v=ITpDrdtGAmo
           | 
           | 1. https://www.bbc.co.uk/programmes/p0198zc1
        
       | billfor wrote:
       | The most interesting thing I learned is that we let people who
       | need Zoloft on the ISS. The FAA will disqualify you for that
       | unless you jump through hoops.
        
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