5 ms·

> It's pretty trivial. Put mass in between you and space. Seems like you quite confident. So go on. Expand on that a bit... its trivial after all. You will te

> It's pretty trivial. Put mass in between you and space. Seems like you quite confident. So go on. Expand on that a bit... its trivial after all. You will teleport all that mass to ELO? Or use tracker beam to capture asteroid and space mine it to smelt shielding. I am super curious how you solve it trivially. edit: You downvote but dont explain this trivial solution. Am I asking too much? Calling someone out to explain something is offensive or something?

phkahler 2y ago
We've had people in space for close to a year, so the trip to Mars shouldn't kill them. Once on mars they'll still need shielding. One option for shelter might be to bore some underground tunnels. A smallish electric tunnel boring machine that could fit in a starship might just be the ticket to building sheltered habitats on Mars. Funny that Elon already has another company that makes these.
- rtkwe 2y ago
  The ISS is situated safely deep inside the Earth's magnetic sheath which protects you from a lot of high energy radiation though. You can use mass for shielding but you also desperately need that mass for cargo too and most cargo isn't going to be as dense as water which makes good shielding. The ISS has some fancier lightweight shielding but has issues with secondary radiation from particles hitting the metal skin of the modules which we'd expect to see on Starship too but higher since it'd be in interplanetary space instead of nicely close to Earth like the ISS.
- dole 2y ago
  Already there as long as they're not filled with squatters. https://www.usgs.gov/news/caves-mars https://www.usgs.gov/news/caves-mars
somenameforme 2y ago
Many basic materials, like water, make great shields if necessary. For Mars one plan is simply to organize the ship such that the water reserves can act as an radiation shield when necessary. You don't need anything particularly massive or overly fancy.
- MeImCounting 2y ago
  The problem is that paradoxically, thicker shields can cause higher doses of radiation due to secondary radiation production. Theres a balance there to minimizing primary and secondary dosage but you cant really get it below a certain threshold without some form of active shielding. Theres a lot of promising ideas for active shielding but they all require alot of power. All this to say that someone on a trip to mars will indeed get a high dose and this is something that needs to be given thought. Its not an intractable problem but it is also not even close to being solved or trivial. Folks on Mars is still quite a ways away. Not impossible or pointless by any means but it will require significant advancements in many domains before we can really do it safely.
  - timschmidt 2y ago
    https://en.wikipedia.org/wiki/Radiotrophic_fungus https://en.wikipedia.org/wiki/Radiotrophic_fungus have also been discussed as an option.
  - somenameforme 2y ago
    The secondary radiation you're talking about is called bremsstrahlung (braking) radiation [1]. This is precisely why water is, to my knowledge, the current leading idea. It works not only as an excellent primary shield but also helps to minimize secondary radiation, and you also naturally have literally tons of it. As an aside, this is why the original Moon missions used simple aluminum. One of the typical angles people who don't think we landed on the Moon used is that to safely get through the Van Allen Belts we would have needed massive lead shielding on the craft, when in reality it was shielded by a pretty thin layer of aluminum, precisely to minimize secondary radiation. If you put that thick lead shielding on the craft that people intuitively think you'd need, it very well could have killed the astronauts. [1] - https://en.wikipedia.org/wiki/Bremsstrahlung https://en.wikipedia.org/wiki/Bremsstrahlung
    - MeImCounting 2y ago
      Polyethylene is similarly a good shield because its got high hydrogen content so is pretty good at moderating neutrons. I image a polyethylene structure containing a layer of water is probably something like what we'll end up settling on. Its also quite strong and would make decent structural components.

phkahler 2y ago

We've had people in space for close to a year, so the trip to Mars shouldn't kill them. Once on mars they'll still need shielding. One option for shelter might be to bore some underground tunnels. A smallish electric tunnel boring machine that could fit in a starship might just be the ticket to building sheltered habitats on Mars. Funny that Elon already has another company that makes these.

rtkwe 2y ago
The ISS is situated safely deep inside the Earth's magnetic sheath which protects you from a lot of high energy radiation though. You can use mass for shielding but you also desperately need that mass for cargo too and most cargo isn't going to be as dense as water which makes good shielding. The ISS has some fancier lightweight shielding but has issues with secondary radiation from particles hitting the metal skin of the modules which we'd expect to see on Starship too but higher since it'd be in interplanetary space instead of nicely close to Earth like the ISS.
dole 2y ago
Already there as long as they're not filled with squatters. https://www.usgs.gov/news/caves-mars https://www.usgs.gov/news/caves-mars

somenameforme 2y ago

Many basic materials, like water, make great shields if necessary. For Mars one plan is simply to organize the ship such that the water reserves can act as an radiation shield when necessary. You don't need anything particularly massive or overly fancy.

MeImCounting 2y ago
The problem is that paradoxically, thicker shields can cause higher doses of radiation due to secondary radiation production. Theres a balance there to minimizing primary and secondary dosage but you cant really get it below a certain threshold without some form of active shielding. Theres a lot of promising ideas for active shielding but they all require alot of power. All this to say that someone on a trip to mars will indeed get a high dose and this is something that needs to be given thought. Its not an intractable problem but it is also not even close to being solved or trivial. Folks on Mars is still quite a ways away. Not impossible or pointless by any means but it will require significant advancements in many domains before we can really do it safely.
- timschmidt 2y ago
  https://en.wikipedia.org/wiki/Radiotrophic_fungus https://en.wikipedia.org/wiki/Radiotrophic_fungus have also been discussed as an option.
- somenameforme 2y ago
  The secondary radiation you're talking about is called bremsstrahlung (braking) radiation [1]. This is precisely why water is, to my knowledge, the current leading idea. It works not only as an excellent primary shield but also helps to minimize secondary radiation, and you also naturally have literally tons of it. As an aside, this is why the original Moon missions used simple aluminum. One of the typical angles people who don't think we landed on the Moon used is that to safely get through the Van Allen Belts we would have needed massive lead shielding on the craft, when in reality it was shielded by a pretty thin layer of aluminum, precisely to minimize secondary radiation. If you put that thick lead shielding on the craft that people intuitively think you'd need, it very well could have killed the astronauts. [1] - https://en.wikipedia.org/wiki/Bremsstrahlung https://en.wikipedia.org/wiki/Bremsstrahlung
  - MeImCounting 2y ago
    Polyethylene is similarly a good shield because its got high hydrogen content so is pretty good at moderating neutrons. I image a polyethylene structure containing a layer of water is probably something like what we'll end up settling on. Its also quite strong and would make decent structural components.