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> But I doubt it would be much riskier than we're currently living our lives here on Earth. You're probably underestimating the risks associated with humans le

> But I doubt it would be much riskier than we're currently living our lives here on Earth. You're probably underestimating the risks associated with humans leaving Earth for any considerable period of time. Radiation is the first issue. NASA will not plan a mission that exposes astronauts to higher than a 3% risk of exposure-induced death. Their reports from 2010 based on all the studies done up to that point put the number of "safe days" at ~0.5-1 years. That assumes a healthy mid-30s non-smoker during a solar minimum. So just getting to Mars would exceed the safe limits, even if we had a very well radiation-shielded base waiting on the planet. Multiple years in space and Mars gravity will also have severe impacts on bone density and muscles. You're never going to be able to fly to Mars, spend a few years, and fly back and resume your life on Earth without long-lasting health effects.

cryptoz 14y ago
> So just getting to Mars would exceed the safe limits This is the problem with your argument that I'm underestimating risks. You're assuming that nobody finds a way to solve this problem or to mitigate the effects of the radiation, and that nobody would be willing to find a way to go even with the health concerns. I know this will be extremely difficult and quite costly, but I think hard work and constant innovation will solve a lot of the specific problems that you pose today. > Multiple years in space and Mars gravity will also have severe impacts on bone density and muscles. You're never going to be able to fly to Mars, spend a few years, and fly back and resume your life on Earth without long-lasting health effects. Prove it. Until you do, I disagree. Also, so what if it's true? Hundreds of millions of people on Earth voluntarily partake in long-lasting negative health effects habits. Why can't "living on Mars for a bit" be one of them?
- smtddr 14y ago
  > Prove it. Until you do, I disagree. Well I can't personally __prove__ it, but I believe the general belief in the science community of prolonged space-travel is that it will most likely mess you up. Probably in more ways than we've even thought of. I don't think, at least with today's tech, that a human can travel to Mars and back and be perfectly okay. http://www.pbs.org/wgbh/nova/space/space-dangers.html http://www.pbs.org/wgbh/nova/space/space-dangers.html http://www.cracked.com/article_19158_the-6-weirdest-dangers-space-travel_p2.html http://www.cracked.com/article_19158_the-6-weirdest-dangers-...
  - danielweber 14y ago
    A lot, not all, but a lot of those people popped up after Bush 41 said that we were going back to the moon and to Mars. NASA heard it was a JFK mission, going to be completed regardless of cost, and told their project managers to put as many things into the mission critical path so they would get funded. When they returned to Congress with a 30-year $450 Billion plan, it was funded with 0 dollars. To be fair, we don't know what 3/8 g will to do someone after a year. For all that it's important, though, it's comical that we haven't put some spinning Skylab space stations up to find out.
- 1123581321 14y ago
  We have already measured bone loss in low gravity environments. http://weboflife.nasa.gov/currentResearch/currentResearchGeneralArchives/weakKnees.htm http://weboflife.nasa.gov/currentResearch/currentResearchGen... Gravity plays an essential role in bone maintenance. You can work this out from first principles if you know anything about biology, or read about NASA's findings. This has been known for a long time, well before humans ever went to space. For example, HG Wells' First Men on the Moon described the very weak chests/ rib cages of the moon's citizens due to low gravity resulting in very low bone density. When the explorers from earth struck them, their chests crumpled like a beetle might on earth. Wells either learned this from other scientists or worked out the logic himself.
  - danielweber 14y ago
    That's microgravity, or what other people call "zero gravity." We honestly don't know how much gravity people need to survive. Your talk of people's chests collapsing because you read it in science fiction is just that: science fiction. HG Wells is great but he's not really a good source of science for modern astrophysics. Odds are, there are many bodily functions that work just fine in a little bit of gravity, and others that scale up as you get more and more gravity. We really need to get some spinning space stations set up to find this stuff out. Unfortunately, NASA has a really big fetish for "let's spend money on microgravity research" instead of just doing the obvious thing of seeing how 1/6 g or 3/8 g affects people and systems.
    - damoncali 14y ago
      To be fair, It's really hard to make 1/6g or 3/8g environments.
    - 1123581321 14y ago
      I was hoping you'd see the Wells item as showing how straightforward and early known is the connection between healthy human bone maintenance and gravity of earth's strength, not science fiction. Certainly the rate of bone loss will be slower in low gravity than in no gravity environments, but it will happen. It must happen to a degree just as surely as missing calcium and other nutrients would harm our bones.
- keeperofdakeys 14y ago
  With current technology (both existing and theoretical), I don't think you'd be able to create a rocket capable of returning with healthy people (even just the returning bit is a practical nightmare). Also, most people underestimate just how big the radiation problem is in space, since we have an earth-sized magnet to mostly protect us (you can't just make a second earth and attach it to your spacecraft). The apollo astronauts are really quite lucky to not be exposed. http://sciencefocus.com/blog/how-apollo-astronauts-avoided-deadly-solar-flare http://sciencefocus.com/blog/how-apollo-astronauts-avoided-d... The "send people to die on mars" idea isn't about developing the technology to allow travelling back and forth, it is a compromise with todays technology to say "let's go and explore, until we have the technology". So you can't shoot down the argument with "when we have the technology...".
jamesaguilar 14y ago
> You're never Unless we can develop drugs that trick the body into maintaining the correct muscle and bone density.
starpilot 14y ago
With Mars there's also that "step outside without a protective suit, suffocate and freeze to death in few minutes" bit: http://en.wikipedia.org/wiki/Atmosphere_of_Mars http://en.wikipedia.org/wiki/Atmosphere_of_Mars
danielweber 14y ago
If you are worried about radiation, a solar minimum is probably the worst time to send someone. Cosmic rays are more prevalent during solar minimums, and shielding against solar flares is non-negotiable anyway. The "safe limits" have already been exceeded by people on the ISS. If NASA has decided that we can't send people into space if there is a 3% chance of them getting cancer at some point later in their lives, then NASA has decided that they aren't going to send anyone to Mars, and it's time for us to find someone else who will.
azov 14y ago
There's at least one person who spent over a year in space during one flight, almost two years combined between several flights. And that's not just in Mars gravity, but in total weightlessness. He's alive and seems to be doing fine. http://en.wikipedia.org/wiki/Valeri_Polyakov http://en.wikipedia.org/wiki/Valeri_Polyakov
- Evgeny 14y ago
  Relevant: Upon landing, Polyakov opted not to be carried the few feet between the Soyuz capsule and a nearby lawn chair, instead walking the short distance. In doing so, he wished to prove that humans could be physically capable of working on the surface of Mars after a long-duration transit phase. That was 18 years ago ...

cryptoz 14y ago

> So just getting to Mars would exceed the safe limits This is the problem with your argument that I'm underestimating risks. You're assuming that nobody finds a way to solve this problem or to mitigate the effects of the radiation, and that nobody would be willing to find a way to go even with the health concerns. I know this will be extremely difficult and quite costly, but I think hard work and constant innovation will solve a lot of the specific problems that you pose today. > Multiple years in space and Mars gravity will also have severe impacts on bone density and muscles. You're never going to be able to fly to Mars, spend a few years, and fly back and resume your life on Earth without long-lasting health effects. Prove it. Until you do, I disagree. Also, so what if it's true? Hundreds of millions of people on Earth voluntarily partake in long-lasting negative health effects habits. Why can't "living on Mars for a bit" be one of them?

smtddr 14y ago
> Prove it. Until you do, I disagree. Well I can't personally __prove__ it, but I believe the general belief in the science community of prolonged space-travel is that it will most likely mess you up. Probably in more ways than we've even thought of. I don't think, at least with today's tech, that a human can travel to Mars and back and be perfectly okay. http://www.pbs.org/wgbh/nova/space/space-dangers.html http://www.pbs.org/wgbh/nova/space/space-dangers.html http://www.cracked.com/article_19158_the-6-weirdest-dangers-space-travel_p2.html http://www.cracked.com/article_19158_the-6-weirdest-dangers-...
- danielweber 14y ago
  A lot, not all, but a lot of those people popped up after Bush 41 said that we were going back to the moon and to Mars. NASA heard it was a JFK mission, going to be completed regardless of cost, and told their project managers to put as many things into the mission critical path so they would get funded. When they returned to Congress with a 30-year $450 Billion plan, it was funded with 0 dollars. To be fair, we don't know what 3/8 g will to do someone after a year. For all that it's important, though, it's comical that we haven't put some spinning Skylab space stations up to find out.
1123581321 14y ago
We have already measured bone loss in low gravity environments. http://weboflife.nasa.gov/currentResearch/currentResearchGeneralArchives/weakKnees.htm http://weboflife.nasa.gov/currentResearch/currentResearchGen... Gravity plays an essential role in bone maintenance. You can work this out from first principles if you know anything about biology, or read about NASA's findings. This has been known for a long time, well before humans ever went to space. For example, HG Wells' First Men on the Moon described the very weak chests/ rib cages of the moon's citizens due to low gravity resulting in very low bone density. When the explorers from earth struck them, their chests crumpled like a beetle might on earth. Wells either learned this from other scientists or worked out the logic himself.
- danielweber 14y ago
  That's microgravity, or what other people call "zero gravity." We honestly don't know how much gravity people need to survive. Your talk of people's chests collapsing because you read it in science fiction is just that: science fiction. HG Wells is great but he's not really a good source of science for modern astrophysics. Odds are, there are many bodily functions that work just fine in a little bit of gravity, and others that scale up as you get more and more gravity. We really need to get some spinning space stations set up to find this stuff out. Unfortunately, NASA has a really big fetish for "let's spend money on microgravity research" instead of just doing the obvious thing of seeing how 1/6 g or 3/8 g affects people and systems.
  - damoncali 14y ago
    To be fair, It's really hard to make 1/6g or 3/8g environments.
  - 1123581321 14y ago
    I was hoping you'd see the Wells item as showing how straightforward and early known is the connection between healthy human bone maintenance and gravity of earth's strength, not science fiction. Certainly the rate of bone loss will be slower in low gravity than in no gravity environments, but it will happen. It must happen to a degree just as surely as missing calcium and other nutrients would harm our bones.
keeperofdakeys 14y ago
With current technology (both existing and theoretical), I don't think you'd be able to create a rocket capable of returning with healthy people (even just the returning bit is a practical nightmare). Also, most people underestimate just how big the radiation problem is in space, since we have an earth-sized magnet to mostly protect us (you can't just make a second earth and attach it to your spacecraft). The apollo astronauts are really quite lucky to not be exposed. http://sciencefocus.com/blog/how-apollo-astronauts-avoided-deadly-solar-flare http://sciencefocus.com/blog/how-apollo-astronauts-avoided-d... The "send people to die on mars" idea isn't about developing the technology to allow travelling back and forth, it is a compromise with todays technology to say "let's go and explore, until we have the technology". So you can't shoot down the argument with "when we have the technology...".

jamesaguilar 14y ago

> You're never Unless we can develop drugs that trick the body into maintaining the correct muscle and bone density.

starpilot 14y ago

With Mars there's also that "step outside without a protective suit, suffocate and freeze to death in few minutes" bit: http://en.wikipedia.org/wiki/Atmosphere_of_Mars http://en.wikipedia.org/wiki/Atmosphere_of_Mars

danielweber 14y ago

If you are worried about radiation, a solar minimum is probably the worst time to send someone. Cosmic rays are more prevalent during solar minimums, and shielding against solar flares is non-negotiable anyway. The "safe limits" have already been exceeded by people on the ISS. If NASA has decided that we can't send people into space if there is a 3% chance of them getting cancer at some point later in their lives, then NASA has decided that they aren't going to send anyone to Mars, and it's time for us to find someone else who will.

azov 14y ago

There's at least one person who spent over a year in space during one flight, almost two years combined between several flights. And that's not just in Mars gravity, but in total weightlessness. He's alive and seems to be doing fine. http://en.wikipedia.org/wiki/Valeri_Polyakov http://en.wikipedia.org/wiki/Valeri_Polyakov

Evgeny 14y ago
Relevant: Upon landing, Polyakov opted not to be carried the few feet between the Soyuz capsule and a nearby lawn chair, instead walking the short distance. In doing so, he wished to prove that humans could be physically capable of working on the surface of Mars after a long-duration transit phase. That was 18 years ago ...