Mining comets/asteroids for water

I'm not sure if this should be in sci.space.science or here.
Its a little about comets and asteroids structure and a little
about technology. Anyway here it goes.

(From here on I will use only the word asteroid not comet, but
consider this to include comets.)

Lets assume that at some time in the future we are having high
rate space travel and that we need lots of water in space. So
it makes economical sense to mine asteroids for water. Lets say
you want to send several kilotons to megatons of water to LEO on
a regular basis. So how do we do this?

One possibility is to send the entire asteroid to LEO. But this
gives you serious constraints on the size of the asteroid. It
is probably better to chose the asteroid based on its composition
than on its size.

Another possibility is to do basically what we do on Earth, break
up the ore into small packets and ship them to the smelting plant.
In this case it would be ship them to LEO. For water from the
asteroid belt this gives some problems, ice will sublimate when
you bring it closer to the sun. To avoid this you would have
to enclose it and maybe refrigerate it. Not impossible to do but a
pain in the ass.

A third possibility is to break up the asteroid into chunks of
an appropriate size. Lets say roughly cubes 50 metres in size.
Too big to sublimate during the trip but small enough to be
shipable.

I am mainly interested in this third possibility. But I don't
really know how to do it. Maybe you could slice a mostly icy
asteroid by passing a wire heated by an electrical current through
it. But I fear the wire would hit some pieces of rock and get stuck.
I'm not sure if breaking it apart with explosives would have any
chance of making big chunks or if it would just make small chunks.

So, does any one have any idea how we should mine asteroids?


Alain Fournier

So, does any one have any idea how we should mine asteroids?

Alain Fournier

Most of the H2O in asteroids is minerally bound. Lots of asteroids
have hit the Moon. We even know where they've hit: the craters are
easily visible.

Yes, some asteroids out past Mars might have concentrations of ice.
But crossing such huge distances takes time, and you run into a
problem called The Time Value of Money: sometimes it doesn't matter
how much something would be worth if you could get it instantly as
long as there's some investment that would pay off sooner.

-michael turner

Michael Turner wrote:

So, does any one have any idea how we should mine asteroids?

Alain Fournier


Most of the H2O in asteroids is minerally bound. Lots of asteroids
have hit the Moon. We even know where they've hit: the craters are
easily visible.

Yes, some asteroids out past Mars might have concentrations of ice.
But crossing such huge distances takes time, and you run into a
problem called The Time Value of Money: sometimes it doesn't matter
how much something would be worth if you could get it instantly as
long as there's some investment that would pay off sooner.

That is a problem. I don't think that it necessarily kills the concept.
It probably does kill the idea of mining the Kuyper Belt to send water
to LEO. But the outer main belt is just a few years away, if you can
mine water there for much less than launching it from Earth (which is
admittedly a very big if) it would be a good business plan.


Alain Fournier

On 20/05/2010 10:06 PM, Alain Fournier wrote:
Michael Turner wrote:

So, does any one have any idea how we should mine asteroids?

Alain Fournier


Most of the H2O in asteroids is minerally bound. Lots of asteroids
have hit the Moon. We even know where they've hit: the craters are
easily visible.

Yes, some asteroids out past Mars might have concentrations of ice.
But crossing such huge distances takes time, and you run into a
problem called The Time Value of Money: sometimes it doesn't matter
how much something would be worth if you could get it instantly as
long as there's some investment that would pay off sooner.

That is a problem. I don't think that it necessarily kills the concept.
It probably does kill the idea of mining the Kuyper Belt to send water
to LEO. But the outer main belt is just a few years away,

The money clock doesn't start when the vehile sets off on its outward
journey to the Kuyper Belt, but much earlier, when vehicle development
begins, because that's when you start paying out money. Throw in the
risk element (which also has a monetary cost), and a viable business
looks very iffy indeed.

Sylvia.

Sylvia Else wrote:
On 20/05/2010 10:06 PM, Alain Fournier wrote:

Michael Turner wrote:

Yes, some asteroids out past Mars might have concentrations of ice.
But crossing such huge distances takes time, and you run into a
problem called The Time Value of Money: sometimes it doesn't matter
how much something would be worth if you could get it instantly as
long as there's some investment that would pay off sooner.


That is a problem. I don't think that it necessarily kills the concept.
It probably does kill the idea of mining the Kuyper Belt to send water
to LEO. But the outer main belt is just a few years away,

The money clock doesn't start when the vehile sets off on its outward
journey to the Kuyper Belt, but much earlier, when vehicle development
begins, because that's when you start paying out money. Throw in the
risk element (which also has a monetary cost), and a viable business
looks very iffy indeed.

Well that is another money clock. What I was thinking about is once you
have the mining settlement working. If you are mining for water in the
outer asteroid belt for use in LEO, then you can deliver your water to
LEO a few years after starting to mine for it. That is workable, a pain
but workable. If you are mining in the Kuyper Belt, you have to know
how much water you will be able to sell in LEO in about two decades.
It is very difficult, probably impossible to run a business that way.

You are correct that if you want to plan an asteroid mining operation
you need to consider the time value of money from the moment you start
preparing your mining operations on Earth and that you will need to
start your investment many years before you start mining. But that would
not be an order of magnitude more time than for your typical mine on
Earth. If asteroid water is sufficiently cheaper than Earth water
it can make sense.


Alain Fournier

On 24/05/2010 7:50 AM, Alain Fournier wrote:

You are correct that if you want to plan an asteroid mining operation
you need to consider the time value of money from the moment you start
preparing your mining operations on Earth and that you will need to
start your investment many years before you start mining. But that would
not be an order of magnitude more time than for your typical mine on
Earth. If asteroid water is sufficiently cheaper than Earth water
it can make sense.

Not an order of mangnitude, perhaps, but certainly multiples. With an
Earth mine, the technology exists, you just have to apply it. For an
asteroid mine, you're starting from a lot further back - you have to
develop the technology first.

Sylvia.

Sylvia Else wrote:
On 24/05/2010 7:50 AM, Alain Fournier wrote:

You are correct that if you want to plan an asteroid mining operation
you need to consider the time value of money from the moment you start
preparing your mining operations on Earth and that you will need to
start your investment many years before you start mining. But that would
not be an order of magnitude more time than for your typical mine on
Earth. If asteroid water is sufficiently cheaper than Earth water
it can make sense.

Not an order of mangnitude, perhaps, but certainly multiples. With an
Earth mine, the technology exists, you just have to apply it. For an
asteroid mine, you're starting from a lot further back - you have to
develop the technology first.

Yes I agree with that. I don't think it would be a wise business plan
to invest serious money for asteroid mining now. But later when we will
have more experience and more technology for doing things on the Moon.
It will be easier to adapt this experience and technology for asteroid
mining. But most importantly, we have to wait until the demand for fuels
and materials in space will be greater, then it might make sense to think
about ways to avoid the gravity penalty we have by exporting everything
from Earth.


Alain Fournier

At Sun, 23 May 2010 17:50:05 EDT Alain Fournier wrote:


Sylvia Else wrote:
On 20/05/2010 10:06 PM, Alain Fournier wrote:

Michael Turner wrote:

Yes, some asteroids out past Mars might have concentrations of ice.
But crossing such huge distances takes time, and you run into a
problem called The Time Value of Money: sometimes it doesn't matter
how much something would be worth if you could get it instantly as
long as there's some investment that would pay off sooner.


That is a problem. I don't think that it necessarily kills the concept.
It probably does kill the idea of mining the Kuyper Belt to send water
to LEO. But the outer main belt is just a few years away,

The money clock doesn't start when the vehile sets off on its outward
journey to the Kuyper Belt, but much earlier, when vehicle development
begins, because that's when you start paying out money. Throw in the
risk element (which also has a monetary cost), and a viable business
looks very iffy indeed.

Well that is another money clock. What I was thinking about is once you
have the mining settlement working. If you are mining for water in the
outer asteroid belt for use in LEO, then you can deliver your water to
LEO a few years after starting to mine for it. That is workable, a pain
but workable. If you are mining in the Kuyper Belt, you have to know
how much water you will be able to sell in LEO in about two decades.
It is very difficult, probably impossible to run a business that way.

You are correct that if you want to plan an asteroid mining operation
you need to consider the time value of money from the moment you start
preparing your mining operations on Earth and that you will need to
start your investment many years before you start mining. But that would
not be an order of magnitude more time than for your typical mine on
Earth. If asteroid water is sufficiently cheaper than Earth water
it can make sense.

It is worth noting that hauling water *up* from the Earth's surface is
costly and there is probably some trade-off point where it might be
cheaper to have water 'meteoroids' *falling* into Earth's orbit rather
that boosting water up Earth's gravity well.



Alain Fournier



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On May 18, 5:26 am, Michael Turner
wrote:
So, does any one have any idea how we should mine asteroids?

Alain Fournier

Most of the H2O in asteroids is minerally bound. Lots of asteroids
have hit the Moon. We even know where they've hit: the craters are
easily visible.

Yes, some asteroids out past Mars might have concentrations of ice.
But crossing such huge distances takes time, and you run into a
problem called The Time Value of Money: sometimes it doesn't matter
how much something would be worth if you could get it instantly as
long as there's some investment that would pay off sooner.

-michael turner


A least some asteroids may be extinct comets. If a comet's perihelion
isn't too close to the sun, it's possible outgassing is gentle enough
to allow an insulating mantle to accumulate. If so, an insulating
mantle can preserve internal volatile ices for a long time.

Conventional wisdom says an extinct comet would come from the Kuiper
Belt or the Oort cloud. And with 30 A.U. apohelions they'd be
traveling too fast for rendezvous while in our neighborhood. This
isn't necessarily true. The Jupiter Trojans may be a source of comets.
There are a lot of short period comets with ~5.2 A.U. apohelions.

And there are main belt comets: http://en.wikipedia.org/wiki/Main-belt_comet

Ice has been detected on Themis:
http://news.ucf.edu/UCFnews/index?pa...2c5363 007e4f

So it is possible water rich main belt asteroids have been nudged into
NEOs via Jupiter perturbations.

An NEO with internal ice might be exploited by a Kuck Mosquitoe.

If it is a more conventional "water rich" asteroid, the hydrated clays
could be harder to exploit. They are about as water rich as the cement
in a sidewalk.