6 ms·

What else can you do with an Interplanetary Transport System?

67 points by cstross 10y ago

okket 10y ago
Thankfully someone mentioned a Dyson swarm [1] in the comments :) [1] https://en.wikipedia.org/wiki/Dyson_sphere#Dyson_swarm https://en.wikipedia.org/wiki/Dyson_sphere#Dyson_swarm
- dghughes 10y ago
  SciShow estimated you'd need to destroy all the planets to get enough raw materials to build a swarm. https://youtu.be/GrM3f7Bil5A?t=185 https://youtu.be/GrM3f7Bil5A?t=185
  - danarmak 10y ago
    We don't really need a full swarm, at least not until we can use it to compute something useful. Even Mercury, the smallest planet, has enough raw material to build more space stations and power-gathering sats than we know what to do with at present. If you had a partial Dyson swarm right now, what would you actually use it for?
    - dghughes 10y ago
      At least the basics of having shelter, food, and water. Maybe at some point we as a civilization could create matter from energy and then create atoms, then finally molecules of whatever we needed. We would also probably want to live long healthy lives maybe even transfer our minds into other bodies or devices. We aren't even a Type I civilization yet so there is lots of planning and inventing to do.
    - Teever 10y ago
      I would use it to build and accelerate Von Neumann probes to colonize the Universe.
throwaway1974 10y ago
Railguns that could accelerate and dump pieces of metal anywhere in world from high orbit. Militaries would drool over the idea of controlled falling meteors for strategic bombing
- Skunkleton 10y ago
  https://en.wikipedia.org/wiki/Kinetic_bombardment https://en.wikipedia.org/wiki/Kinetic_bombardment I think we would all be better off if we didn't develop even more effective ways of killing each other...
  - zlatan_todoric 10y ago
    Ramen. We really need to get into primary schools subjects such as meditation, ethics, moral and "care for humanity" instead of having people get educated to go into military and "drool over weapons to kill more effectively".
    - Skunkleton 10y ago
      At least in this case there are treaties that prevent space based weapons platforms.
      - zlatan_todoric 10y ago
        Well, that would work if people/government don't break treaties of all kind on daily basis. Solution must be in roots not a patch on top of pile (of bullshit we created over time)
        cstross 10y ago
        a) it's kind of hard to hide a launch system where the fueled-up booster stack on the pad weighs two and a half times as much as a Saturn V and the launch is visible with the naked eye from a hundred miles away. b) There is a reason we don't use Trident D-5 SLBMs (or the Russian equivalent) for precision conventional explosive strikes on targets which otherwise require long range bombers with intricate in-flight refuelling arrangements to hit: something about not scaring the other folks with strategic nukes into thinking we've initiated a first strike and hitting the big red end of the world button. TLDR: even the big guys don't mess with space-based or sub-orbital weaponry. The risk of a misunderstanding is non-trivial and the perceived costs are far too high.
le-mark 10y ago
Assemble an Orion ie nuclear pulse propulsion ship in orbit. These can theoretically acheive .1c, Proxima Centari in 40 years (give or take).
- jerf 10y ago
  I'm not sure there's any time in the near future where we're going to be allowed to loft that much fissile material into orbit, due to the risks of the takeoff exploding and spreading it everywhere. Personally I think the risks are overstated, but that doesn't affect the reality that we're not going to be able to do that any time soon. We're not going to have Orion drives until we can get the fissile material from space. Also it's not clear to me that an Orion taking off from a very-near-Earth orbit is a good idea, either. I'm not sure how to reconcile apocalyptic-sounding fears about EM pulses from nuclear explosions with an Orion departing from LEO.
flibble 10y ago
#7 Lifting Coca Cola LED billboard
dandare 10y ago
So how many sunshades (or square meters of mirror foil) could we get to orbit to regulate global warming?
- aetherson 10y ago
  The earth, as it turns out, is pretty big. I don't think that you can get meaningful amounts of sunshades into orbit via rocket launches from Earth, even really, really efficient rocket launches from Earth. As a wild-and-crazy concept, doing the lunar space elevator thing that Stross mentions in his blog post would allow you to build a manufacturing facility on the moon that turned regolith into a sunshade and then ship them up the lunar space elevator and drop them off into Earth orbit at a moderately reasonable cost. If you aren't too concerned about the mass of a sunshade, there are lots of ways to constitute them, so this seems like it would be one of the easier manufacturing jobs you might imagine locating on the Moon.
- BurningFrog 10y ago
  Gold is supposedly the most malleable metal. One ounce - the size of a quarter - can be hammered out to 10 square meters. I'll let someone else do the math.
  - mathgorges 10y ago
    The radius of Earth (according to Google) is 6371 km π * 6371^2 ≈1.28e8 km^2 = 1.28e11 m^2 = 1.28e10 oz of gold So, you would need 800 million pounds of gold, which would cost (at current spot price of 1324.80/oz) almost 18 trillion dollars. Gold is probably not the best material for this
    - pacificmint 10y ago
      800 million pounds is about 360,000 metric tons. The total amount of gold we have mined so far is somewhere around 170,000 metric tons. So if you used all the gold in the world, you'd only have about half of what you need. At the same time, I was surprised that it is even in the same ballpark.
FullMtlAlcoholc 10y ago
You could construct massive artificial satellites that have permanent human habitation if we could shield ourselves from the radiation. It's fascinating that we could conceivably have people born, spending most of their life, and dying in a completely hostile enviornment and that it will be in space before it will be under water. I didn't watch all of Elon's presentation and I don't know if he mentioned this. However, I would think that a space elevator of some sort or a massive lunar manufacturing facility would be required to efficiently create all the components of an Interplanetary Transport System.. Upwards of 80% of the mass of going into space is just propellant to escape gravity. Even if the rockets are reusable, we won't truly be an interplanetary civilization until most of the components needed for space travel are actually manufactured in space or in extremely low gravity situations
- YZF 10y ago
  It's a key part of the proposal. The propellant is shuttled over to the spaceship in orbit via multiple runs of a refuelling rocket. I guess the downside of constructing or assembling anything anywhere but earth today is that it's going to be a lot more expensive and complicated. Perhaps once Mars has some critical mass the construction can shift to there as the gravity is lower. The moon is farther away than orbit and also doesn't really have a lot in the way of accessible natural resources. Elon touched briefly on the topic of a moon settlement... Despite all the talk of a space elevator I think it's still science fiction. Elon's plan is all based on existing technology...
  - FullMtlAlcoholc 10y ago
    I guess I was imagining more of an Interplanetary Transport System that was at least self-sustaining if not profitable. The lack of resources on the Moon could be solved by finding an appropriate near-earth asteroid to mine. The ideal 1st candidate based on potential mineral wealth ($87 billion, but I don't believe those numbers are very accurate) and proximity to earth (a measly .1au, or 9 million miles during its solar periohelion :) is Anteru I believe. Here we are, on the precipice of colonizing Mars in possibly my 80 yr old father's lifetime, witnessing perhaps mankind's greatest and boldest feat yet and I'm getting greedy and thinking "Yawn, who cares. Let me know when the Interplanetary TRADE System is profitable and indefinitely self-sustaining." I'd try to visit Mars at least once . When it reaches a level of infrastructure and economic development of early 18th century British or other Euro colonies is when it's looking likely I would consider making a one way trip there.
critium 10y ago
Space Data Centers -- we got tons of power, just need to figure out how to vent all that heat.
- bhhaskin 10y ago
  Turns out space is really cold.
  - neaden 10y ago
    But vacuum is a very poor conductor of heat.
    - solotronics 10y ago
      I think you can have large radiator panels and circulate a cooling fluid or gas. Most (all?) of the cooling effect comes from infrared radiation.
innertracks 10y ago
The Airship to Orbit concept [1] caught my attention a while ago. There's something rather elegant about floating one's way to (almost) orbit. [1] http://www.jpaerospace.com/ http://www.jpaerospace.com/
cylinder714 10y ago
Regarding fun-in-zero-gee: velvet cargo nets. Sorted! Seriously, doesn't the recent news about higher mortality among lunar astronauts throw all this talk about colonization into doubt? http://www.nature.com/articles/srep29901 http://www.nature.com/articles/srep29901
- maxander 10y ago
  I mean, if that sort of long-term mortality risk is a big factor for the colonists, things are going really well. Even if all of Musk's plans work out, living somewhere as inhospitable as Mars (not to mention falling out of the sky at many times the speed of sound) will entail shouldering substantial near-term risks regardless. The hope is that there's enough smart people with a sufficiently weak sense of self-preservation.

67 points by cstross 10y ago

okket 10y ago

Thankfully someone mentioned a Dyson swarm [1] in the comments :) [1] https://en.wikipedia.org/wiki/Dyson_sphere#Dyson_swarm https://en.wikipedia.org/wiki/Dyson_sphere#Dyson_swarm

dghughes 10y ago
SciShow estimated you'd need to destroy all the planets to get enough raw materials to build a swarm. https://youtu.be/GrM3f7Bil5A?t=185 https://youtu.be/GrM3f7Bil5A?t=185
- danarmak 10y ago
  We don't really need a full swarm, at least not until we can use it to compute something useful. Even Mercury, the smallest planet, has enough raw material to build more space stations and power-gathering sats than we know what to do with at present. If you had a partial Dyson swarm right now, what would you actually use it for?
  - dghughes 10y ago
    At least the basics of having shelter, food, and water. Maybe at some point we as a civilization could create matter from energy and then create atoms, then finally molecules of whatever we needed. We would also probably want to live long healthy lives maybe even transfer our minds into other bodies or devices. We aren't even a Type I civilization yet so there is lots of planning and inventing to do.
  - Teever 10y ago
    I would use it to build and accelerate Von Neumann probes to colonize the Universe.

throwaway1974 10y ago

Railguns that could accelerate and dump pieces of metal anywhere in world from high orbit. Militaries would drool over the idea of controlled falling meteors for strategic bombing

Skunkleton 10y ago
https://en.wikipedia.org/wiki/Kinetic_bombardment https://en.wikipedia.org/wiki/Kinetic_bombardment I think we would all be better off if we didn't develop even more effective ways of killing each other...
- zlatan_todoric 10y ago
  Ramen. We really need to get into primary schools subjects such as meditation, ethics, moral and "care for humanity" instead of having people get educated to go into military and "drool over weapons to kill more effectively".
  - Skunkleton 10y ago
    At least in this case there are treaties that prevent space based weapons platforms.
    - zlatan_todoric 10y ago
      Well, that would work if people/government don't break treaties of all kind on daily basis. Solution must be in roots not a patch on top of pile (of bullshit we created over time)
      - cstross 10y ago
        a) it's kind of hard to hide a launch system where the fueled-up booster stack on the pad weighs two and a half times as much as a Saturn V and the launch is visible with the naked eye from a hundred miles away. b) There is a reason we don't use Trident D-5 SLBMs (or the Russian equivalent) for precision conventional explosive strikes on targets which otherwise require long range bombers with intricate in-flight refuelling arrangements to hit: something about not scaring the other folks with strategic nukes into thinking we've initiated a first strike and hitting the big red end of the world button. TLDR: even the big guys don't mess with space-based or sub-orbital weaponry. The risk of a misunderstanding is non-trivial and the perceived costs are far too high.

le-mark 10y ago

Assemble an Orion ie nuclear pulse propulsion ship in orbit. These can theoretically acheive .1c, Proxima Centari in 40 years (give or take).

jerf 10y ago
I'm not sure there's any time in the near future where we're going to be allowed to loft that much fissile material into orbit, due to the risks of the takeoff exploding and spreading it everywhere. Personally I think the risks are overstated, but that doesn't affect the reality that we're not going to be able to do that any time soon. We're not going to have Orion drives until we can get the fissile material from space. Also it's not clear to me that an Orion taking off from a very-near-Earth orbit is a good idea, either. I'm not sure how to reconcile apocalyptic-sounding fears about EM pulses from nuclear explosions with an Orion departing from LEO.

flibble 10y ago

#7 Lifting Coca Cola LED billboard

dandare 10y ago

So how many sunshades (or square meters of mirror foil) could we get to orbit to regulate global warming?

aetherson 10y ago
The earth, as it turns out, is pretty big. I don't think that you can get meaningful amounts of sunshades into orbit via rocket launches from Earth, even really, really efficient rocket launches from Earth. As a wild-and-crazy concept, doing the lunar space elevator thing that Stross mentions in his blog post would allow you to build a manufacturing facility on the moon that turned regolith into a sunshade and then ship them up the lunar space elevator and drop them off into Earth orbit at a moderately reasonable cost. If you aren't too concerned about the mass of a sunshade, there are lots of ways to constitute them, so this seems like it would be one of the easier manufacturing jobs you might imagine locating on the Moon.
BurningFrog 10y ago
Gold is supposedly the most malleable metal. One ounce - the size of a quarter - can be hammered out to 10 square meters. I'll let someone else do the math.
- mathgorges 10y ago
  The radius of Earth (according to Google) is 6371 km π * 6371^2 ≈1.28e8 km^2 = 1.28e11 m^2 = 1.28e10 oz of gold So, you would need 800 million pounds of gold, which would cost (at current spot price of 1324.80/oz) almost 18 trillion dollars. Gold is probably not the best material for this
  - pacificmint 10y ago
    800 million pounds is about 360,000 metric tons. The total amount of gold we have mined so far is somewhere around 170,000 metric tons. So if you used all the gold in the world, you'd only have about half of what you need. At the same time, I was surprised that it is even in the same ballpark.

FullMtlAlcoholc 10y ago

You could construct massive artificial satellites that have permanent human habitation if we could shield ourselves from the radiation. It's fascinating that we could conceivably have people born, spending most of their life, and dying in a completely hostile enviornment and that it will be in space before it will be under water. I didn't watch all of Elon's presentation and I don't know if he mentioned this. However, I would think that a space elevator of some sort or a massive lunar manufacturing facility would be required to efficiently create all the components of an Interplanetary Transport System.. Upwards of 80% of the mass of going into space is just propellant to escape gravity. Even if the rockets are reusable, we won't truly be an interplanetary civilization until most of the components needed for space travel are actually manufactured in space or in extremely low gravity situations

YZF 10y ago
It's a key part of the proposal. The propellant is shuttled over to the spaceship in orbit via multiple runs of a refuelling rocket. I guess the downside of constructing or assembling anything anywhere but earth today is that it's going to be a lot more expensive and complicated. Perhaps once Mars has some critical mass the construction can shift to there as the gravity is lower. The moon is farther away than orbit and also doesn't really have a lot in the way of accessible natural resources. Elon touched briefly on the topic of a moon settlement... Despite all the talk of a space elevator I think it's still science fiction. Elon's plan is all based on existing technology...
- FullMtlAlcoholc 10y ago
  I guess I was imagining more of an Interplanetary Transport System that was at least self-sustaining if not profitable. The lack of resources on the Moon could be solved by finding an appropriate near-earth asteroid to mine. The ideal 1st candidate based on potential mineral wealth ($87 billion, but I don't believe those numbers are very accurate) and proximity to earth (a measly .1au, or 9 million miles during its solar periohelion :) is Anteru I believe. Here we are, on the precipice of colonizing Mars in possibly my 80 yr old father's lifetime, witnessing perhaps mankind's greatest and boldest feat yet and I'm getting greedy and thinking "Yawn, who cares. Let me know when the Interplanetary TRADE System is profitable and indefinitely self-sustaining." I'd try to visit Mars at least once . When it reaches a level of infrastructure and economic development of early 18th century British or other Euro colonies is when it's looking likely I would consider making a one way trip there.

critium 10y ago

Space Data Centers -- we got tons of power, just need to figure out how to vent all that heat.

bhhaskin 10y ago
Turns out space is really cold.
- neaden 10y ago
  But vacuum is a very poor conductor of heat.
  - solotronics 10y ago
    I think you can have large radiator panels and circulate a cooling fluid or gas. Most (all?) of the cooling effect comes from infrared radiation.

innertracks 10y ago

The Airship to Orbit concept [1] caught my attention a while ago. There's something rather elegant about floating one's way to (almost) orbit. [1] http://www.jpaerospace.com/ http://www.jpaerospace.com/

cylinder714 10y ago

Regarding fun-in-zero-gee: velvet cargo nets. Sorted! Seriously, doesn't the recent news about higher mortality among lunar astronauts throw all this talk about colonization into doubt? http://www.nature.com/articles/srep29901 http://www.nature.com/articles/srep29901

maxander 10y ago
I mean, if that sort of long-term mortality risk is a big factor for the colonists, things are going really well. Even if all of Musk's plans work out, living somewhere as inhospitable as Mars (not to mention falling out of the sky at many times the speed of sound) will entail shouldering substantial near-term risks regardless. The hope is that there's enough smart people with a sufficiently weak sense of self-preservation.