
What else can you do with an Interplanetary Transport System? - cstross
http://www.antipope.org/charlie/blog-static/2016/09/what-else-can-you-do-with-a-bi.html
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FullMtlAlcoholc
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

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neaden
What's the appeal of people living in orbit though? By that I don't mean
industries that could happen there, but people actually having kids, growing
up, and dying. I don't see the rationale for a permanent population in orbit
anymore then we have one in Antarctica or a deep sea oil platform.

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zardo
Once the cost is low enough, the rationale is its cheaper to make new land
than to buy land on a crowded planet. If we hit that point, you would expect
massive space colonization.

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zbyte64
Wouldn't it be easier to place the living module on an inhospitable part of
the planet then launching it into orbit? There are lots of deserts and tundras
available.

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zardo
That is the case now, and it's likely to be the case for a long time to come.

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okket
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)

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dghughes
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)

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danarmak
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?

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dghughes
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.

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

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BurningFrog
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.

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mathgorges
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

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BurningFrog
Thanks for the math help :)

That's looks like the size to cover the entire planet and completely remove
all sunlight. But to counteract global warming, we'd need a much smaller area.
If it's 1%, we're down to a mere $180B.

I'm sure you're right that other materials would be far more economical. My
gut says Aluminum.

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maxander
Given that the costs of global warming are talked in the trillions, this means
that this silly thought experiment would actually be a _rationally economical
solution_.

Which just illustrates how terrible global warning really is, I suppose.

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cylinder714
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)

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maxander
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.

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innertracks
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/)

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flibble
#7 Lifting Coca Cola LED billboard

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throwaway1974
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

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Skunkleton
[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...

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zlatan_todoric
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".

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Skunkleton
At least in this case there are treaties that prevent space based weapons
platforms.

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zlatan_todoric
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)

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cstross
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.

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

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jerf
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.

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

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bhhaskin
Turns out space is really cold.

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neaden
But vacuum is a very poor conductor of heat.

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solotronics
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.

