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On the contrary, Mars has all the resources of asteroids but the advantage of a water cycle that has concentrated and reformed minerals like on Earth. The abili

On the contrary, Mars has all the resources of asteroids but the advantage of a water cycle that has concentrated and reformed minerals like on Earth. The ability to process the atmosphere directly is a massive and under-rated advantage. MOXIE proves it’s not just possible but feasible to generate fuel (carbon monoxide) and oxidizer (oxygen) from the Martian atmosphere, and nitrogen and even a bit of water (hydrogen and oxygen) as well as argon are available anywhere on the planet. The “let’s just build cylinders” (which I think we should eventually do!!) often strikes me as a knee jerk contrarian position, an attempt to avoid hard questions about environment, and a “grass is always greener in fields further in the future and with less solid understanding.” Planetary bodies with water cycles (or a history of them) are rich. Airless bodies have massive difficulties that are often handwaved away. And now we have powered flight (without needing propellant) demonstrated. Mars really is a much better place to establish a permanent human presence.

Baeocystin 5y ago
I think a lot of it will ultimately depend on whether Mars has enough gravity to avoid the health issues that we see in orbital microgravity environments. Do we have any idea, based on our experiences with space stations & lunar landings? Genuine question, I'd really like to know.
- rbanffy 5y ago
  Mars has about a third of the Earth's, so it's not microgravity and is about twice as powerful as the Moon's. There are not many reasons to expect it will create huge health issues for earthlings but if you spend too much time on Mars without exercising on a centrifuge, adapting back to Earth could be a problem. There will be some loss of muscular mass, at least.
  - Baeocystin 5y ago
    I suppose the core of my question is just wondering what the shape of the g-dose response curve is. 1g is nominal. 0g has significant long-term problems, even with countermeasures like daily exercise. Is the physiologic response between the two extremes linear? My intuition says no, but I don't have real data to check.
    - mncharity 5y ago
      > what the shape of the g-dose response curve is And to make matters more complex, that dose could be spectrum, rather than a constant value. Eg, spend X hours doing Y in the compact ~2 meter centrifuge at Z g, plus ... and ... .
    - babesh 5y ago
      Just one data point. The astronauts on the ISS spend 2 hours a day exercising. That apparently works in that once they get back on Earth after 6 months, they don’t have issues with weakened musculature. ISS is a microgravity environment.
- mncharity 5y ago
  > Do we have any idea IIRC, largely no - it's a very open research question. > I'd really like to know I fuzzily recall seeing an applicable NASA space medicine slide deck last year, but I'm not quickly finding it - sorry. > depend on whether Mars has enough gravity While it's common to oversimplify and exaggerate minimum-size constraints on rotational gravity, even if greater than Mars gravity is needed almost continuously, it might perhaps turn out easier engineering to maintain that on Mars (with mounted spinning things, or maybe pods in curving tunnels) than in space (spinning habitats). You still have vacuum at hand, but also support and workspace - things are more easily stopped, stood next to, and kicked.
- Supermancho 5y ago
  > Do we have any idea https://rendia.com/resources/insights/vision-problems-in-space/#:~:text=A%20study%20found%20that%20the,people%20are%20sleeping%20on%20Earth https://rendia.com/resources/insights/vision-problems-in-spa.... and https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_human_body https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_h...
c048 5y ago
Building 'cylinders' gives us an environment that's a lot easier to control, manage and safeguard compared to a whole planet. Most planets will be entirely hostile to complex earth based life to begin with. They'll require either complex terraforming or some sort of isolated environment, and that's not even bringing up issues concerning gravity. Furthermore, in future wars planets would also be far easier, bigger and immovable targets compared to asteroids and space-stations. Just look up what happens when you drop a 10ton tungsten rod from outer-space. Thanks to gravity, when it hits the ground it has the same impact of a small nuclear device. When humanity starts to create colonies outside of earth, I expect most planets will only become fully automated mining colonies. Colonizing planets is a Star Trek fantasy that, most likely, will not be worth it.
- kortilla 5y ago
  > Just look up what happens when you drop a 10ton tungsten rod from outer-space. Thanks to gravity, when it hits the ground it has the same impact of a small nuclear device. That’s... not as good as a nuclear device? Susceptibility to 10 ton tungsten rods is pretty lame to worry about when a 10 ton actual nuclear bomb would be so much worse.
  - c048 5y ago
    You're missing the point. The point is how easy it becomes to destroy planetary targets once you start having an extra-earth presence as a society. You literally drop heavy stuff from orbit and you have a nuke. You need an actual, guidable, nuke (or self propelled object) to have the same effect on a space station or asteroid.
    - PicassoCTs 5y ago
      Does that make Tesla a nuclear power though? Or do they need to conduct a test first?
      - c048 5y ago
        You may not realize it yet, but they've already become our new overlords. Do you think they bothered with getting a certified driving license for that puppet they put in the car they launched a few years back? They don't care about our earther laws. Yet there he is, drifting in space.
elihu 5y ago
I agree with that. The way I look at is is that Mars has the resources needed to support a population and interplanetary travel, whereas the asteroids are (probably) where the lucrative mining opportunities are. Eventually we may colonize the belt, but if so we'll probably do it by using Mars as the local gas station and supermarket.
eloff 5y ago
There is a HUGE difference in metals concentration in planetary crust and an asteroid that's mostly that element. Also a huge difference in gravity if you want the materials offworld. You don't have to colonize them, but mining asteroids makes tons of sense.
garmaine 5y ago
> On the contrary, Mars has all the resources of asteroids but the advantage of a water cycle that has concentrated and reformed minerals like on Earth. The water cycle concentrates diffuse elements into usable mineral deposits, yes. But those elements are only diffuse in the first place because of the planetary environment. The base abundance of industrially useful elements in asteroids can be tens, hundreds, or thousands of times higher than Earth (or Mars) precisely because these materials sank to the core or mantle of planets, or get chemically locked up in expensive to refine oxides. Indeed many of the rare metals we prize are actually of asteroidal origin, because they have been completely depleted in the Earth's crust in geologic antiquity. What's more, chondritic or M-class asteroids typically have extremely accessible minerals, such as pure metals already in reduced form, or mixtures of loosely compacted minerals that can be sorted with a crusher and a centrifuge.
spfzero 5y ago
One thing you can’t ever change about Mars is its gravity though. All of our biological construction over billions of years was in 1g. Maybe we could thrive from birth, for 100 years or so, in one third G, but I’m skeptical. Even more so on an asteroid. Even on Earth, reduced muscle mass is associated with poorer health outcomes. To maintain that in reduced gravity would mean a lot of hours per day in resistance exercise.
- lmm 5y ago
  Going from 1g to micro/no-gravity seems like a much more dramatic change than going from 1 to 0.3, so I think that's an argument for going to Mars ahead of asteroids.
  - spfzero 5y ago
    That’s what I thought I said. Mars bad, asteroids worse.
- inglor_cz 5y ago
  It is possible that we will hack our own biology to grow stronger muscles without exercise or at least not as much exercise. Famously, Neanderthals, a very close species, were more muscular than us. It probably translated to higher consumption of food, though; a muscular body needs to eat a lot to maintain itself. That might be a problem on Mars.
- BelenusMordred 5y ago
  > To maintain that in reduced gravity would mean a lot of hours per day in resistance exercise. There's zero evidence for this at all. We have no experimental data on living in partial gravity, only microgravity(zero-G). It may be perfectly fine, it may be just as bad as no gravity, we truly don't know. There was a module for the ISS that was designed to test this but it got scrapped, a massive waste IMO, as it seems to be one of the most outstanding questions we have right now for space biology. Other big issues like radiation exposure is well understood.

Baeocystin 5y ago

I think a lot of it will ultimately depend on whether Mars has enough gravity to avoid the health issues that we see in orbital microgravity environments. Do we have any idea, based on our experiences with space stations & lunar landings? Genuine question, I'd really like to know.

rbanffy 5y ago
Mars has about a third of the Earth's, so it's not microgravity and is about twice as powerful as the Moon's. There are not many reasons to expect it will create huge health issues for earthlings but if you spend too much time on Mars without exercising on a centrifuge, adapting back to Earth could be a problem. There will be some loss of muscular mass, at least.
- Baeocystin 5y ago
  I suppose the core of my question is just wondering what the shape of the g-dose response curve is. 1g is nominal. 0g has significant long-term problems, even with countermeasures like daily exercise. Is the physiologic response between the two extremes linear? My intuition says no, but I don't have real data to check.
  - mncharity 5y ago
    > what the shape of the g-dose response curve is And to make matters more complex, that dose could be spectrum, rather than a constant value. Eg, spend X hours doing Y in the compact ~2 meter centrifuge at Z g, plus ... and ... .
  - babesh 5y ago
    Just one data point. The astronauts on the ISS spend 2 hours a day exercising. That apparently works in that once they get back on Earth after 6 months, they don’t have issues with weakened musculature. ISS is a microgravity environment.
mncharity 5y ago
> Do we have any idea IIRC, largely no - it's a very open research question. > I'd really like to know I fuzzily recall seeing an applicable NASA space medicine slide deck last year, but I'm not quickly finding it - sorry. > depend on whether Mars has enough gravity While it's common to oversimplify and exaggerate minimum-size constraints on rotational gravity, even if greater than Mars gravity is needed almost continuously, it might perhaps turn out easier engineering to maintain that on Mars (with mounted spinning things, or maybe pods in curving tunnels) than in space (spinning habitats). You still have vacuum at hand, but also support and workspace - things are more easily stopped, stood next to, and kicked.
Supermancho 5y ago
> Do we have any idea https://rendia.com/resources/insights/vision-problems-in-space/#:~:text=A%20study%20found%20that%20the,people%20are%20sleeping%20on%20Earth https://rendia.com/resources/insights/vision-problems-in-spa.... and https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_human_body https://en.wikipedia.org/wiki/Effect_of_spaceflight_on_the_h...

c048 5y ago

Building 'cylinders' gives us an environment that's a lot easier to control, manage and safeguard compared to a whole planet. Most planets will be entirely hostile to complex earth based life to begin with. They'll require either complex terraforming or some sort of isolated environment, and that's not even bringing up issues concerning gravity. Furthermore, in future wars planets would also be far easier, bigger and immovable targets compared to asteroids and space-stations. Just look up what happens when you drop a 10ton tungsten rod from outer-space. Thanks to gravity, when it hits the ground it has the same impact of a small nuclear device. When humanity starts to create colonies outside of earth, I expect most planets will only become fully automated mining colonies. Colonizing planets is a Star Trek fantasy that, most likely, will not be worth it.

kortilla 5y ago
> Just look up what happens when you drop a 10ton tungsten rod from outer-space. Thanks to gravity, when it hits the ground it has the same impact of a small nuclear device. That’s... not as good as a nuclear device? Susceptibility to 10 ton tungsten rods is pretty lame to worry about when a 10 ton actual nuclear bomb would be so much worse.
- c048 5y ago
  You're missing the point. The point is how easy it becomes to destroy planetary targets once you start having an extra-earth presence as a society. You literally drop heavy stuff from orbit and you have a nuke. You need an actual, guidable, nuke (or self propelled object) to have the same effect on a space station or asteroid.
  - PicassoCTs 5y ago
    Does that make Tesla a nuclear power though? Or do they need to conduct a test first?
    - c048 5y ago
      You may not realize it yet, but they've already become our new overlords. Do you think they bothered with getting a certified driving license for that puppet they put in the car they launched a few years back? They don't care about our earther laws. Yet there he is, drifting in space.

elihu 5y ago

I agree with that. The way I look at is is that Mars has the resources needed to support a population and interplanetary travel, whereas the asteroids are (probably) where the lucrative mining opportunities are. Eventually we may colonize the belt, but if so we'll probably do it by using Mars as the local gas station and supermarket.

eloff 5y ago

There is a HUGE difference in metals concentration in planetary crust and an asteroid that's mostly that element. Also a huge difference in gravity if you want the materials offworld. You don't have to colonize them, but mining asteroids makes tons of sense.

garmaine 5y ago

> On the contrary, Mars has all the resources of asteroids but the advantage of a water cycle that has concentrated and reformed minerals like on Earth. The water cycle concentrates diffuse elements into usable mineral deposits, yes. But those elements are only diffuse in the first place because of the planetary environment. The base abundance of industrially useful elements in asteroids can be tens, hundreds, or thousands of times higher than Earth (or Mars) precisely because these materials sank to the core or mantle of planets, or get chemically locked up in expensive to refine oxides. Indeed many of the rare metals we prize are actually of asteroidal origin, because they have been completely depleted in the Earth's crust in geologic antiquity. What's more, chondritic or M-class asteroids typically have extremely accessible minerals, such as pure metals already in reduced form, or mixtures of loosely compacted minerals that can be sorted with a crusher and a centrifuge.

spfzero 5y ago

One thing you can’t ever change about Mars is its gravity though. All of our biological construction over billions of years was in 1g. Maybe we could thrive from birth, for 100 years or so, in one third G, but I’m skeptical. Even more so on an asteroid. Even on Earth, reduced muscle mass is associated with poorer health outcomes. To maintain that in reduced gravity would mean a lot of hours per day in resistance exercise.

lmm 5y ago
Going from 1g to micro/no-gravity seems like a much more dramatic change than going from 1 to 0.3, so I think that's an argument for going to Mars ahead of asteroids.
- spfzero 5y ago
  That’s what I thought I said. Mars bad, asteroids worse.
inglor_cz 5y ago
It is possible that we will hack our own biology to grow stronger muscles without exercise or at least not as much exercise. Famously, Neanderthals, a very close species, were more muscular than us. It probably translated to higher consumption of food, though; a muscular body needs to eat a lot to maintain itself. That might be a problem on Mars.
BelenusMordred 5y ago
> To maintain that in reduced gravity would mean a lot of hours per day in resistance exercise. There's zero evidence for this at all. We have no experimental data on living in partial gravity, only microgravity(zero-G). It may be perfectly fine, it may be just as bad as no gravity, we truly don't know. There was a module for the ISS that was designed to test this but it got scrapped, a massive waste IMO, as it seems to be one of the most outstanding questions we have right now for space biology. Other big issues like radiation exposure is well understood.