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> There are nitrates on mars The martian atmosphere is 2.8% N2. For comparison, Earths atmoshpere is 78.08% N2, while also being more than 100x as dense. And E

> There are nitrates on mars The martian atmosphere is 2.8% N2. For comparison, Earths atmoshpere is 78.08% N2, while also being more than 100x as dense. And Earth already has soil, and a developed nitrogen cycle, while Mars doesn't. So there is nowhere near enough Nitrogen in-situ on Mars to support any form of agriculture. It has to be brought from Earth. > mars has enough gravity to prevent bone loss https://www.ucsf.edu/news/2017/07/407806/traveling-mars-will-wreak-havoc-our-bodies-can-we-prevent-it https://www.ucsf.edu/news/2017/07/407806/traveling-mars-will... So yes, lowered gravity has negative impacts on our bones and physiology in general. The gravity on Mars is 1/3 that of Earth. And that's after spending several months in-transit at microgravity. > But yes, it does mean bringing your own air and being self sufficient, but we do both of those things on the ISS already The ISS is not self sufficient, and relies on continuos supply runs from earth: https://en.wikipedia.org/wiki/Uncrewed_spaceflights_to_the_International_Space_Station https://en.wikipedia.org/wiki/Uncrewed_spaceflights_to_the_I...

notfish 3y ago
Nitrates on earth range from 10-50 mg/kg in soil, on mars they make up 1100ppm = 0.1% = 1mg/kg, so in the extreme you can convert 10% of martian land to soil. Seems like plenty. We just don’t know if the 1/3 gravity will cause bone loss problems - going to the moon is the best way to study it, but who knows. Probably, people will just age 3x faster in terms of bone mass on mars. https://en.m.wikipedia.org/wiki/Spaceflight_osteopenia https://en.m.wikipedia.org/wiki/Spaceflight_osteopenia And yeah, the first years of a mars colony are gonna be dependent on earth. We’d definitely make sure we have enough rockets that they can abort if shit goes south on supply missions, but there’s no reason earth can’t supply them at first.
- usrbinbash 3y ago
  Nitrogen in Earths soil is present in the form of Ammonia, and derived substances. Occurring naturally, it is the product of microbial nitrogen fixation of diazotrophic bacteria, and subsequent biological processing. Plants can use these compounds directly. Nitrates on mars will probably be in the form of nitrate salts. Btw. agriculture also requires soil. Which the martian regolith isn't. > We’d definitely make sure we have enough rockets that they can abort if shit goes south on supply missions Have enough rockets where? On mars? Using what fuel? Using what ground installations like scaffolds and launch pads? Also, launching between Mars and Earth is only possible during specific time windows. For an Earth-Mars transit, these occur ~once every 2 years. So if "shit goes south" outside these windows, the amount of rockets won't matter.
  - anticensor 3y ago
    > Also, launching between Mars and Earth is only possible during specific time windows. No. It is always possible, but the optimal windows happen every two years. There is another 2nd optimal window, that happens every 5.5 months, which flies by Venus before continuing on to Earth/Mars.
    - usrbinbash 3y ago
      You are of course correct. I should have said: The lowest energy option for a Mars transfer happens every 24 months. Transfer outside that window is possible, but requires more energy, which increases the transfer time, limits the payload, or both.
nine_k 3y ago
Earth crust has relatively small amounts of iron, or nickel, or silver, but it has areas with high concentration of these, so large as to enable massive metallurgy on Earth. Chances are, Mars may have local concentrations of nitrous minerals (as does Earth), and these can be used to run a large enough agriculture. Few plants know how to consume atmospheric nitrogen anyway. Air pressure and temperature can be maintained below transparent domes, greenhouse-style. Dim sunlight looks like a much bigger problem, which can't be fixed by any terraforming.
- usrbinbash 3y ago
  > Chances are, Mars may have local concentrations of nitrous minerals Which would have to be found, ideally near the equator (otherwise landing and solar power generation is going to be a problem), mined and transported. And since Nitrous minerals aren't fertilizer, it would have to be processed (which is an energy intensive process even on earth, where we get to use atmospheric Nitrogen in the Haber-Bosch-Process). And of course there is no soil on mars, so we have to bring that as well.
  - nine_k 3y ago
    Indeed! This turns a nigh-impossible task into a just technically very hard one. Of course we won't be able to do this now, and still won't be in 10-15 years. In 30 years it's hard to predict: there can be a huge technological breakthrough, or a total loss of interest and regress in capabilities.
    - usrbinbash 3y ago
      Well, it's "a just technically very hard one" right now. Because, we could, technically, just send fertilizer, and soil, from Earth. The question I am asking isn't "is it possible". The question I am asking is "is it worth it". I see a lot of comparisons with Columbus, colonising America and the first Lunar landing flying around in such discussions. Well, all of these, and in fact most grand far-fetched undertakings of mankind, as un-romantic as that may sound, were the result of a cost-benefit analysis; Columbus expected to find a valueable trade-route. Colonising America promised resources, taxes and geopolitical power. Landing on the Moon showed off who got the biggest most badass rockets to a geostrategic opponent in the middle of a cold war centered around, well, rockets. There is a reason no man has been on the moon since the 70s. Trying to colonise Mars promises...what exactly?

notfish 3y ago

Nitrates on earth range from 10-50 mg/kg in soil, on mars they make up 1100ppm = 0.1% = 1mg/kg, so in the extreme you can convert 10% of martian land to soil. Seems like plenty. We just don’t know if the 1/3 gravity will cause bone loss problems - going to the moon is the best way to study it, but who knows. Probably, people will just age 3x faster in terms of bone mass on mars. https://en.m.wikipedia.org/wiki/Spaceflight_osteopenia https://en.m.wikipedia.org/wiki/Spaceflight_osteopenia And yeah, the first years of a mars colony are gonna be dependent on earth. We’d definitely make sure we have enough rockets that they can abort if shit goes south on supply missions, but there’s no reason earth can’t supply them at first.

usrbinbash 3y ago
Nitrogen in Earths soil is present in the form of Ammonia, and derived substances. Occurring naturally, it is the product of microbial nitrogen fixation of diazotrophic bacteria, and subsequent biological processing. Plants can use these compounds directly. Nitrates on mars will probably be in the form of nitrate salts. Btw. agriculture also requires soil. Which the martian regolith isn't. > We’d definitely make sure we have enough rockets that they can abort if shit goes south on supply missions Have enough rockets where? On mars? Using what fuel? Using what ground installations like scaffolds and launch pads? Also, launching between Mars and Earth is only possible during specific time windows. For an Earth-Mars transit, these occur ~once every 2 years. So if "shit goes south" outside these windows, the amount of rockets won't matter.
- anticensor 3y ago
  > Also, launching between Mars and Earth is only possible during specific time windows. No. It is always possible, but the optimal windows happen every two years. There is another 2nd optimal window, that happens every 5.5 months, which flies by Venus before continuing on to Earth/Mars.
  - usrbinbash 3y ago
    You are of course correct. I should have said: The lowest energy option for a Mars transfer happens every 24 months. Transfer outside that window is possible, but requires more energy, which increases the transfer time, limits the payload, or both.

nine_k 3y ago

Earth crust has relatively small amounts of iron, or nickel, or silver, but it has areas with high concentration of these, so large as to enable massive metallurgy on Earth. Chances are, Mars may have local concentrations of nitrous minerals (as does Earth), and these can be used to run a large enough agriculture. Few plants know how to consume atmospheric nitrogen anyway. Air pressure and temperature can be maintained below transparent domes, greenhouse-style. Dim sunlight looks like a much bigger problem, which can't be fixed by any terraforming.

usrbinbash 3y ago
> Chances are, Mars may have local concentrations of nitrous minerals Which would have to be found, ideally near the equator (otherwise landing and solar power generation is going to be a problem), mined and transported. And since Nitrous minerals aren't fertilizer, it would have to be processed (which is an energy intensive process even on earth, where we get to use atmospheric Nitrogen in the Haber-Bosch-Process). And of course there is no soil on mars, so we have to bring that as well.
- nine_k 3y ago
  Indeed! This turns a nigh-impossible task into a just technically very hard one. Of course we won't be able to do this now, and still won't be in 10-15 years. In 30 years it's hard to predict: there can be a huge technological breakthrough, or a total loss of interest and regress in capabilities.
  - usrbinbash 3y ago
    Well, it's "a just technically very hard one" right now. Because, we could, technically, just send fertilizer, and soil, from Earth. The question I am asking isn't "is it possible". The question I am asking is "is it worth it". I see a lot of comparisons with Columbus, colonising America and the first Lunar landing flying around in such discussions. Well, all of these, and in fact most grand far-fetched undertakings of mankind, as un-romantic as that may sound, were the result of a cost-benefit analysis; Columbus expected to find a valueable trade-route. Colonising America promised resources, taxes and geopolitical power. Landing on the Moon showed off who got the biggest most badass rockets to a geostrategic opponent in the middle of a cold war centered around, well, rockets. There is a reason no man has been on the moon since the 70s. Trying to colonise Mars promises...what exactly?